THE INTERPRETATION OF TENSE IN DISCOURSE 
Bonnie Lynn Webber 
Department of Computer & Information Science 
University of Pennsylvania 
Philadelphia PA 19104-6389 
Abstract 
This paper gives an account of the role tense plays in 
the listener's reconstruction of the events and situations a 
speaker has chosen to describe. Several new ideas are 
presented: (a) that tense is better viewed by analogy with 
definite NPs than with pronouns; (b) that a narrative has a 
temporal focus that grounds the context-dependency of 
tense; and (c) that focus management heuristics can be 
used to track the movement of temporal focus. 1 
1. Introduction 
My basic premise is that in processing a narrative text, 
a listener is building up a representation of the speaker's 
view of the events and situations being described and of 
their relationship to one another. This representation, 
which I will call an eventJsituatlon structure or e/s 
structure, reflects the listener's best effort at interpreting 
the speaker's ordering of those events and situations in 
time and space. The listener's problem can therefore be 
viewed as that of establishing where in the evolving els 
structure to attach the event or situation described in the 
next clause. My claim is that the discourse interpretation of 
tense contributes to the solution of this problem. 
This work on the discourse interpretation of tense is 
being carried out in the context of a larger enterprise 
whose goal is an account of explicit anaphoric reference to 
events and situations, as in Example 1. 
Example 1 
It's always been presumed that when the glaciers 
receded, the area got very hot. The Folsum men 
couldn't adapt, and they died out. That's what's 
supposed to have happened./t's the textbook dogma. 
But it's wrong. They were human and smart. They 
adapted their weapons and culture, and they survived. 
Example 1 shows that one may refer anaphorically to 
structured entities built up through multiple clauses. Thus 
an account of how clauses arrange themselves into 
structures is necessary to an account of event reference. 2 
IThis work was papally supported by ARO grant DAA29-84og-0027, 
NSF grant MCS-8219116-CER, and DARPA grant N00014-85-K-0018 to 
the University of Pennsylvania, and by DARPA grant N00014-aS.-C-0012 to 
UNISYS. 
=Other parts of ~e entemrise include a ganeraJ mechanism for 
individuating composite entities made up of ones separately introduced 
I20, 21J and a representation for events that aJlow for anaphoric reference 
to both particular events and situations and to abstractions thereof \[16\], 
In this paper, I will relate the problem of building up an 
e/s structure to what has been described as the 
anaphoric property of tense \[7, 11, 6, 1, 12\] and of relative 
temporal adverbials\[18\]. Anaphora are expressions 
whose specification is context-dependent. Tense and 
relative temporal adverbials, I interpret as specifying 
positions in an evolving els structure. My view of their 
anaphoric nature is that the particular positions they can 
specify depend on the current context. And the current 
context only makes a few positions accessible. (This I will 
claim to be in contrast with the ability of temporal 
subordinate clauses and noun phrases (NPs) to direct the 
listener to any position in the evolving structure.) 
The paper is organized as follows: In Section 2, I 
discuss tense as an anaphoric device. Previous work in 
this area has discussed how tense is anaphoric, claiming 
as well that it is like a pronoun. While agreeing as to the 
source of the anaphoric character of tense, I do not think 
the analogy with pronouns has been productive. In 
contrast, I discuss what I believe to be a more productive 
analogy between tense and definite noun phrases. 
Previous work has focussed on the interpretation of 
tensed clauses in simple linear narratives (i.e., narratives 
in which the order of underlying events directly 
corresponds to their order of presentation). 3 Here the 
most perplexing question involves when the next clause in 
a sequence is interpreted as an event or sequence 
coincident with the previous one and when, as following 
the previous one \[4, 6, 12\]. In Section 3, I show that if one 
moves beyond simple linear narratives, there are more 
options. In terms of the framework proposed here, there 
may be more than one position in the evolving e/s 
structure which can provide a context for the 
interpretation of tense. Hence there may be more than one 
position in els structure which tense can specify and 
which the new event or situation can attach to. 
To model the possible contexts, I introduce a 
discourse-level focussing mechanism - temporal focus or 
TF - similar to that proposed for interpreting pronouns and 
definite NPs \[17\]. I give examples to show that change of 
TF is intimately bound up with narrative structure. To keep 
track of and predict its movement, I propose a set of focus 
heuristics: one Focus Maintenance Heuristic, predicting 
regular movement forward, two Embedded Discourse 
Heuristics for stacking the focus and embarking on an 
embedded narrative, and one Focus Resumption 
ZAnother persOn currently addressing the interpretation of tense and 
aspect in more complex narratives is Nakhimovsky I9, 10\]. Though we are 
addressing somewhat different issues, his approach seems very 
compatible with this one. 
147 
Heuristic for returning and resuming the current narrative. 
The need for each of these is shown by example. 
In Section 4, I show that relative temporal adverbials 
display the same anaphoric property as simple tense. 
That the interpretation of tense should be entwined 
with discourse structure in this way should not come as a 
surprise, as a similar thing has been found true of other 
discourse anaphora \[5\]. 
2. Tense as Anaphor 
Tense does not seem prima facie anaphoric: an 
isolated sentence like "John went to bed" or "1 met a man 
who looked like a basset hound = appears to make sense 
without previously establishing when it happened. On the 
other hand, if some time or event is established by the 
context, tense will invariably be interpreted with respect to 
it, as in: 
Example 2 
After he finished his chores, John went to bed. 
John partied until 3arn. He came home and went 
to bed. 
In each case, John's going to bed is linked to an explictly 
mentioned time or event. This linkage is the anaphoric 
property of tense that previous authors have described. 
Hinrichs\[6\] and Bauerle\[1\], following McCawley 
\[7\] and Partee \[11\], showed that it is not tense per se that 
is interpreted anaphorically, but that part of tense called by 
Reichenbach \[14\] reference time. 4 According to 
Reichenbach, the interpretation of tense requires three 
notions: speech time (ST), event time lET), and 
reference time (RT). RT is the time from which the 
event/situation described in the sentence is viewed. It may 
be the same as ST, as in 
present perfect: ET<RT=ST 
John has climbed Aconcagua and Mt. McKinley. 
simple presenti ET=RT=ST 
John is in the lounge. 
the same as El', as in 
simple past: ET=RT<ST 
John climbed Aconcagua. 
simple future: ST<ET=RT 
John will climb Aconcagua. 
in between ET and ST, as in 
past perfect: ET<RT<ST 
John had climbed Aconcagua. 
or following both El" and ST (looking bac~ to them), as in 
f.uture perfect: ST<ET<RT 
John will have climbed Mt. McKinley. 
That it is RT that it is interpreted anaphorically, and not 
either El" or tense as a whole can be seen by considering 
Example 3. 
.Example 3 
John went to the hospital. 
He had twisted his ankle on a patch of ice. 
It is not the El" of John's twisting his ankle that is 
interpreted anaphorically with respect to his going to the 
hospital. Rather, it is the RT of the second clause: its ET is 
interpreted as prior to that because the clause is in the 
past perfect tense (see above). 
Having said that it is the RT of tense whose 
interpretation is anaphoric, the next question to ask is what 
kind of anaphoric behavior it evinces. In previous work, 
tense is claimed to behave like a pronoun. Partee 
\[12\] makes the strongest case, claiming that pronouns 
and tense display the same range of antecedent-anaphor 
linkages: 
Oeictic Antecedents 
pro: She left reel (said by a man crying on the stoop) s 
tense: I left the oven onl (said by a man to his wife 
in the car) 
Indefinite Antecedents 
pro: I bought a banana. I took it home with me. 
tense: I bought a banana. I took it home with me. 
<1 took it home after I bought it.> 
Bound Variables 
pro: Every man thinks he is a genius. 
tense: Whenever Mary phoned, Sam was asleep. 
<Mary phoned at time t, Sam was asleep at t> 
Donkey Sentences 
pro: Every man who owns a donkey beats it. 
tense: Whenever Mary phoned on a Friday, Sam was 
asleep. 
<Mary phoned at time t on a Friday, Sam was 
asleep at t on that Friday> 
Because of this similarity, Partee and others have claimed 
that tense is like a pronoun. Their account of how time is 
then seen to advance in simple linear narratives is 
designed, in part, to get around the problem that while 
pronouns coospecify with their antecedents, the RT of 
clause N cannot just co-specify the same time as the 
previous clause \[6, 12, 4\]. 
There is another option though: one can draw an 
analogy between tense and definite NPs, which are also 
anaphoric. Support for this analogy is that, like a definite 
4Hinrichs' work is discussed as well in \[12l. 
Sl believe thai the deictic use of pronouns is infelicitous. In this example, 
the speake¢ is dis~'aught and making no attemp( to be cooperauve. It 
happens. But that doesn't mean thai pronouns have deictic antecedents. I 
include the example here because it is part of Partee's argument. 
148 
NP, tense can cause the listener to create something new. 
With a definite NP, that something new is a new discourse 
entity \[19\]. With tense, I will say for now that it is a new 
time at which the event or situation is interpreted as 
ocouring, s If one looks at texts other than simple linear 
narratives, this ability becomes clear, as the following 
simple example shows: 
Example 4 
I was at Mary's house yesterday. 
We talked about her brother. 
He spent 5 weeks in Alaska with two fdends. 
Together, they made a successful assault on Denali. 
Mary was very proud of him. 
The event of Mary's brother spending five weeks in Alaska 
is not interpreted as occurring either coincident with or 
after the event of my conversation with Mary. Rather, the 
events corresponding to the embedded narrative in the 
third and fourth clause are interpreted at a different spatio- 
temporal location than the conversation. That it is before 
the conversation is a matter of world knowledge. In the els 
structure for the whole narrative, the tense of the third 
clause would set up a new position for the events of the 
embedded narrative, ordered prior to the current position, 
to site these events. 
The claimed analogy of tense with pronouns is based 
on the similarity in antecedent-anaphor linkages they 
display. But notice that definite NPs can display the same 
linkages in two different ways: (1) the definite NP can co- 
specify with its antecedent, as in the a. examples below, 
and (2) the definite NP can specify a new entity that is 
'strongly' associated with the antecedent and is unique by 
virtue of that association, as in the b. examples below 7 
Deictic Antecedents 
The car won't startl (said by a man crying on the stoop) 
Indefinite Antecedents 
a. I picked up a banana. Up close, I noticed the banana 
was too green to eat. 
b. I picked up a banana. The skin was all brown. 
Bound Variables 
a. Next to each car, the owner of the carwas sleeping 
soundly. 
b. In each car, the engine was idling quietly. 
Donkey Sentences 
a. Everyone who wants a car must fix the car himself. 
b. Everyone who owns a Ford tunes the engine himself. 
Thus the range of antecedent-anaphor behavior that 
Partee calls attention to argues equally for an analogy 
between tense and pronouns as for an analgoy between 
tense and definite NPs. 
eAfter I say more about Me structure construction, I will be able to claim 
that tense can cause the listener to create a new position in e/s structure 
at which to attach the event or situation described in its associated clause. 
7Clark & Marshall \[2\] are among those who have described ~e 
necessary "common knowledge" that must be assumable by speaker and 
listener about the association for the spedfication to be successful. 
However, there are two more features of behavior to 
consider: On the one hand, as noted earlier, definite NPs 
have a capability that pronouns lack 8. That is, they can 
introduce a new entity into the discourse that is 'strongly' 
associated with the antecedent and is unique by virtue of 
that association, as in the b. examples above. Example 4 
shows that tense has a similar ability. Thus, a stronger 
analogy can be drawn between tense and definite NPs. 
On the other hand, definite NPs have the capability to 
move the listener away from the current focus to a 
particular entity introduced earlier or a particular entity 
associated with it. This ability tense lacks. While tense 
can set up a new node in els structure that is strongly 
associated with its 'antecedent', it does not convey 
sufficient information to position that node precisely - for 
example, precisely relative to some other event or 
situation the listener has been told about. Thus its 
resemblance to definite NPs is only partial, although it is 
stronger-than its resemblance to pronouns. To locate a 
node precisely in e/s structure requires the full temporal 
correlate of a definite NP - that is, a temporal subordinate 
clause or a definite NP itself, as in Example 5. 
Example 5 
The bus reached the Stadium, terminal for the suburban 
bus services. Here De Witt had to change to a streetcar. 
The wind had abated but the rain kept falling, almost 
vertically now. He was travelling to a two o'clock 
appointment at Amsterdam police headquarters in the 
center of town, and he was sure to be late. 
When De Witt got to the police president's office, he 
telephoned his house. 
\[adapted from Hans Koning, De Witt's War\] 
Notice that without the "when" clause, the simple past 
tense of "he telephoned his house" would be anaphorically 
interpreted with respect to the "reaching the Stadium" 
event, as happening sometime after that. A new node 
would be created in els structure ordered sometime after 
the "reaching the Stadium" event. On the other hand, with 
the "when" clause, that new node can be ordered more 
precisely after the "reaching the Stadium" event. By 
association with its "antecedent" (the "travelling to the 
appointment" event), it can be ordered after the 
achievement of that event. 
There is another advantage to be gained by pushing 
further the analogy between tense and definite NPs that 
relates to the problem tackled in \[6, 4, 12\] of how to 
reconcile the anaphoric nature of tense with the fact that 
the event or situation described in the next clause varies 
as to whether it is taken to be coincident with, during, 
before or after the event or situation described in the 
previous clause. This I will discuss in the next section, 
after introducing the notion of temporal focus. 
aexcept for "pronouns of laziness" which can evoke and specify new 
entities through the use of previous dascriptions 
149 
3. Temporal Focus 
In this section, I give a more specific account of how 
the discourse interpretation of tense relates to e/s 
structure construction. 
At any point N in the discourse, there is one node of 
e/s structure that provides a context for the interpretation 
of the RT of the next ctause. I will call it the temporal 
focus or TF. There are three possibilities: (1) the FIT of 
the next clause will be interpreted anaphorically against 
the current TF, (2) the "IF will shift to a different node of 
Ms structure- either one already in the structure or one 
created in recognition of an embedded narrative - and the 
RT interpreted with respect to that node, or (3) the "IF will 
return to the node previously labeUed TF, after completing 
an embedded narrative, as in (2), and the RT interpreted 
there, These three behaviors are described by four focus 
management heuristics described in this section: a Focus 
Maintenance Heuristic, two Embedded Discourse 
Heuristics and a Focus Resumption Heuristic. 9 
In \[21\], I presented a control structure in which these 
heuristics were applied serially. The next heuristic would 
only be applied when the prediction of the previous one 
was rejected on grounds of "semantic or pragmatic 
inconsistency'. I now believe this is an unworkable 
hypothesis. Maintaining it requires (1) identifying grounds 
for such rejection and (2) arguing that one can reject 
proposals, independent of knowing the alternatives. 
I now don't believe that either can be done. It is rarely 
the case that one cannot come up with a story linking two 
events and/or Situations. Thus it would be impossible to 
reject a hypothesis on grounds of inconsistency. All one 
can say is that one of such stodes might be more plausible 
than the others by requiring, in some sense not explored 
here, fewer inferences. ~° 
Thus I would now describe these heuristics as running 
in parallel, with the most plausible prediction being the one 
that ends up updating both sis structure and the TF. For 
clarity in presentation though, I will introduce each 
heuristic separately, at the point that the next example 
calls for it. 
3.1. Interpreting RT against "iF 
Before presenting the temporal focus management 
heuristics, I want to say a bit more about what it can mean 
to interpret the RT of the next clause against the current 
TF. This discussion points out the additional advantage to 
9Rohrer \[15\] suggest= that ~ere may exist a set of possible temporal 
referents, possibly ordered by saliency, among which ~e tense in a 
sentence may find its reference time, but donsn't elaborate how. That is 
~a only thing I have seen thin comes close to eta current proposal. 
l°Ccain arid Steedman \[3\] make a similar argument about prepositional 
phrase (PP) attachmenL For example, it is not impossible for a cat to own a 
telescope - e.g., by inheritance from its former owner. Thus "a ~ wi~ a 
telescope" is not art inconsistent description. However, it must compete 
with other plausible interpretations like "seeing wi~ a telescope" in "i saw == 
cat with a telescope'. 
be gained by pushing the analogy between tense and 
definite NPs. 
As I noted above, a definite NP can specify an entity 
'strongly' associated with its antecedent. One might thus 
consider what is 'strongly' associated with an event. One 
answer to this question appears in two separate papers in 
this volume \[8, 13\], each ascribing a tripartite structure to 
the way we view and talk about events. This structure 
consists of a preparatory phase, a culmination, and a 
consequence phase, to use the terminology of \[8\]. (Such a 
structure is proposed, in part, to give a uniform account of 
how the interpretation of temporal adverbials interacts with 
the interpretation of tense and aspect.) 
Nodes in e/s structure correspond to events and 
situations, as the speaker conceives them. If one 
associates such a structure with the node labelled the 
currant TF, then one can say that 'strongly' associated 
with it are events and situations that could make up its 
preparatory phase, culmination or consequence phase. 
Like a definite NP, the RT of tense may either co-specify 
the current TF or set up a new node in e/s structure 
'strongly' associated with the TF. In the latter case, its 
corresponding event or situation will be interpreted as 
being part of one of these three phases, depending on the 
speaker and listener's assumed shared knowledge. 
Since, arguably, the most common way of perceiving the 
wodd is as an ordered sequence of events, this will 
increase the plausibility of interpreting the next event or 
situation as (1) still associated with the current TF and (21 
part of the consequence phase of that event (i.e., after it). 
On the other hand, this 'strong association' treatment no 
longer limits anaphorio interpretation to "co-specify" or 
"right after= as in \[4, 6, 12\]. The event described can be 
anaphorically associated with the the whole event 
structure (Example 6a), the consequence phase (Example 
6b - "right after'), or the preparatory phase (Example 6c - 
"before'). 
Example 6 
a. John walked across Iowa. He thought about Mary, 
who had run off with a computational linguist. 
b. John walked across Iowa. He crossed the state line 
at Council Bluffs and headed west through Nebraska. 
c. John walked across iowa. He started in Sioux City 
and headed east to Fort Dodge. 
Deciding which of these three options holds in a given 
case demands an appeal to world knowledge (e.g. which 
actions can be performed simultaneously by a single 
agent). This is yet another area demanding further study 
and is not treated in this paper. 11 
11Mark Steedman shares responsibility for this idea, which is aJso 
mentioned in his paper wi~ Marc Moons in this volume \[8\]. 
150 
3.2. Focus Maintenance and Focus Movement 
The following pair of examples illustrate the simplest 
movement of temporal focus in a discourse and its link 
with e/s structure construction. 
Example 7a 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses. 
3. Unfortunately the roses failed to cheer her up. 
Example To 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses. 
3. He picked out 5 red ones, 3 white ones and one 
pale pink. 
Since the first two clauses are the same in these 
examples, I will explain them together. 
With no previous temporal focus (TF) established 
prior to clause 1, the listener creates a new node of e/s 
structure, ordered prior to now, to serve as TF. "IF sites 
the anaphoric interpretation of RT 1, which, because clause 
1 is in the simple past, also sites ET 1. This is shown 
roughly in Figure 3-1. 
Figure 3-1: E/S structure after processing clause 1 
The first heuristic to be introduced is a Focus 
Maintenance Heuristic (FMH). 
After interpreting dause N, the new TF is the most 
recent TF - i.e., the node against which RT N was 
interpreted. 
The most recent "IF is cotemporal with RT I. This new TF 
now provides a site for interpreting RT 2. Since clause 2 is 
past perfect, ET 2 is interpreted as being prior to RT 2. E/s 
structure is now roughly as shown in Figure 3-2. 
E't'~ 
¢'.~z. s"~ E.~\].. 
Flgure 3-2: E/S structure after processing clause 2 
Applying the FMH again, RT 2 is the new TF going into 
clause 3. Examples 7a and 7b here diverge in what 
subsequently happens to the TF. 
In 7a, RT 3 can be anaphorically interpreted as 
immediately following the TF. Since RT 3 in turn directly 
sites ET 3 (clause 3 being simple past), the "failing event" 
is interpreted as immediately following the "going over to 
Mary's house • event. This is shown roughly in Figure 3-3. 
(TF is shown already moved forward by the FMH, ready 
for the interpretation of the next clause, if any.) 
nk 
Figure 3-3: E/S structure after processing clause 7a-3 
To get the most plausible interpretation of 7b - i.e., 
where the "rose picking • event is interpreted anaphorically 
with respect to the "flower shop" event - requires a second 
heuristic, which I will call an Embedded Discourse 
Heuristic. This will be EDH-1, since I will introduce 
another Embedded Discourse Heuristic a bit later. 
If ET N is different from RTN='rF, treat utterance N as 
the beginning of an embedded narrative, reassign ET N 
to TF (stacking the previous value of TF, for possible 
resumption later) and try to interpret RTN+ 1 against this 
new TF. 
By this heuristic winning the plausibility stakes against the 
FMH, TF is reassigned to ET 2 (stacking the previous TF, 
which is sited at RT2=RT I=ET 1). and RT 3 is anaphorically 
interpreted as following this new TF. As before, ET 3 is 
sited directly at RT 3 (since simple past), so the "picking 
out the roses" event is viewed as immediately following 
the "stopping at the florist" event. This is shown roughly in 
Figure 3-4. 
. k~" 
Figure 3-4: E/S structure after processing clause 7b-3 
Now consider the following extension to example 7b. 
Example 7c 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses. 
3. He picked out 5 red ones, 3 white ones and 
one pale pink. 
4. Unfortunately they failed to cheer her up. 
First notice that clauses 2-3 form an embedded narrative 
that interrupts the main narrative of John's visit to Mary's. 
The main sequence of events that begins with clause 1 
resumes at clause 4. Now consider the anaphoric 
interpretation of tense. Clauses 1-3 are interpreted as in 
Example 7b (cf. Figure 3-4). The problem comes in the 
interpretation of Clause 7c-4. 
151 
To get the most plausible interpretation requires a third 
heuristic which I will call a Focus Resumption Heuristic 
(FRH). 
At the transition bade from an embedded nan'alive, 
the TF prior to the embedding (stacked by an 
Embedded Discourse Heuristic) can be resumed. 
Using this heuristic, the previously stacked TF (sited at 
RT2=RT1-ET 1 - the "going to Mary's house" event) 
becomes the new TF, and RT 4 is interpreted as directly 
following it. Since clause 7c-4 is simple past, the "failing" 
event is again correctly interpreted as immediately 
following the "going over to Mary's house" event. This is 
shown roughly in Figure 3-5. 
E~ 
I | ~ L 
~F 
Figure 3-5: EJS structure after processing clause 7c-4 
I have already noted that, like a definite NP, tense can 
cause the listener to create a new node in e/s structure to 
site its RT. What I want to consider here is the 
circumstances under which a reader is likely to create a 
new node of e/s structure to interpret RTN.I, rather than 
using an existing node (i.e., the current TF, one associated 
with the previous event (if not the TF) or a previous, 
stacked TF). 
One circumstance I mentioned earlier was at the 
beginning of a discourse: a reader will take an 
introductory sentence like Snoopy's famous first line 
It was a dark and stormy night. 
and start building up a new e/s structure with one node 
corresponding to ST and another node siting RT and ET, 
Generalizing this situation to the beginning of embedded 
narratives as well, I propose a second Embedded 
Discourse Heuristic (EDH-2): 
If clause N+t is interpreted as beginning an 
embedded narrative, create a new node of e/s 
structure and assign it to be TF. Stack the previous 
value of TF, for possible resumption later. 
EDH-2 differs from EDH-1 in being keyed by the new 
clause itself: there is no existing event node of els 
structure, different from the currant TF, which the 
embedded narrative is taken to further describe. 
EDH-2 explains what is happening in interpreting the 
third clause of Example 4. Even though all the clauses of 
Example 4 are simple past, with ET=RT, the third clause is 
most plausibly interpreted as describing an event which 
has ocoured prior to the *telling about her brother" event. 
EDH-2 provides the means of interpreting the tense in an 
embedded narrative whose events may occur either 
before or even after the current TF. 
Example 4 
1. I was at Mary's house yesterday. 
2. We talked about her brother. 
3. He spent 5 weeks in Alaska with two friends. 
4. Together, they made a successful assault on Denali. 
5. Mary was very proud of him. 
Notice that the focus stacking specified in EDH-2 enables 
the correct interpretation of clause 4-5, which is most 
plausibly interpreted via the FRH as following the "telling 
about her brother" event. 
EDH-2 is also relevant for the interpretation of NPs 
headed by de-verbal nouns (such as "trip', "installation', 
etc.). While such a NP may describe an event or situation, 
there may not be enough information in the NP itself or in 
its clause to locate the event or situation in els structure 
(of. "my trip to Alaska" versus "my recent/upcoming trip to 
Alaska'). On the other hand, EDH-2 provides a way of 
allowing that information to come from the subsequent 
discourse. That is, if the following clause or NP can be 
interpreted as describing a particular event/situation, the 
original NP and the subsequent NP or clause can be taken 
as co-specifying the same thing. Roughly, that is how I 
propose treating cases such as the following variation of 
Example 4: 
Example 8 
1. I was talking with Mary yesterday. 
2. She told me about her trip to Alaska. 
3. She spent five weeks there with two friends, 
and the three of them climbed Denali. 
The NP "her trip to Alaska" does not of itself cause an 
addition to e/s structure. 12 Rather, application of EDH-2 
to the interpretation of clause 5-3 results in the creation of 
a new node of els structure against which its RT is sited. 
Other reasoning results in clause 3 and "her trip to Alaska" 
being taken as co-specifying the same event. This is what 
binds them together and associates "her trip to Alaska" 
with a node of e/s structure. 
Rnally, notice that there will be an ambiguity when 
more than heuristic makes a plausible prediction, as in the 
following example: 
Example 9 
1. I told Frank about my meeting with Ira. 
2. We talked about ordering a butterfly. 
It is plausible to take the second utterance as the 
beginning of an embedded narrative, whereby EDH-2 
results in the "talking about" event being interpreted 
against a new node of els structure, situated prior to the 
"telling Frank" event. (In this case, "we" is Ira and me.) It is 
also plausible to take the second utterance as continuing 
the current narrative, whereby FMH results in the "talking 
about" event being interpreted with respect to the "telling 
Frank" event. (In contrast here, "we" is Frank and me.) 
1=It does, of course, result in Re creation of a discourse entity \[19\]. The 
relationship I see between t~e listener's e/s structure and his'her 
dlacoume model is discussed in \[21 \]. 
152 
4. Temporal Focus and Temporal Adverbials 
So far I have only shown that clauses containing no 
other time-related constructs than tense can be interpreted 
anaphorically against more than one site in ale structure. 
Now I want to show, at least by example, that what I have 
proposed holds for clauses containing relative temporal 
adverbs as well. Relative temporal adverbials must be 
interpreted with respect to some other time \[18\]. So 
consider the italicized forms in the following brief texts. 
John became the captain of Penn's squash team. 
He was previously captain of the Haverford team. 
John left for London on Sunday. 
Tuesday he went to Cambridge. 
Tuesday John went to Cambridge. 
On Sunday, he left for London. 
Previously is interpreted with respect to the previously 
mentioned "becoming captain" event: it was before that 
that he was captain at Haverford. In the second case, the 
adverbial On Sunday, given no previous link in the 
discourse, is interpreted with respect to ST. However, 
Tuesday is then interpreted with respect to the event of 
John's leaving for London: it is interpreted as the Tuesday 
after that event. The third case is the reverse. 
What I want to show is that, as before, the same four 
heuristics predict the sites in els structure that may 
provide a context for a relative temporal adverbial. 
Consider the following. 
Example 10a 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses. 
3. After five minutes of awkwardness, he gave her 
the flowers 
Example 10b 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses. 
3. After 20 minutes of waiting, he left with the bouquet 
and fairly ran to Mary's. 
I will use ADV to refer to the interpretation of the "after" 
adverbial. In these cases, what is sited by TF is the 
beginning of the interval. What in turn sites the RT of the 
main clause is the end of the interval. 
The processing of the first two clauses is just the same 
as in examples 7a and b. From here, the two examples 
diverge. 
In 10a-3, the beginning of ADV is most plausibly 
interpreted with respect to the TF. The end of ADV in turn 
provides an anaphoric interpretation point for RT 3. Since 
ET 3 is interpreted as coincident with RT 3 (clause 3 being 
simple past), the "rose giving" event is interpreted as 
immediately following John's getting to Mary's house. This 
is shown roughly in figure 4-1. 
Figure 4-1: E/S structure after processing clause 10a-3 
In 10b-3, the interpretation due to FMH is less 
plausible than that due to EDH-I. EDH-1 re-assigns TF to 
ET2, where the beginning of ADV is then sited. The end of 
ADV in turn provides an anaphoric interpretation point for 
RT 3. Since ET 3 is sited at RT 3, the "leaving with the 
bouquet" event is sited at the end of the twenty minutes of 
waiting. This is shown roughly in Figure 4-2. 
,.._.,_3 
la¢>v "t'~" 
Figure 4-2: E/S structure after processing clause 10b-3 
An interesting question to consider is whether a 
speaker would ever shift the TF as modelled by the FRH 
or the EDH-2, while simultaneously using a relative 
temporal adverbial whose interpretation would have to be 
linked to the new TF, as in example 11 (movement via FRH) 
and example 12 (movement via EDH-2). 
Example 11 
1. John went over to Mary's house. 
2. On the way, he had stopped by the flower shop for 
some roses 
3. He picked out 5 red ones, 3 white ones and one 
pale pink. 
4. After 5 minutes of awkwardness, he gave her the 
flowers. 
Example 12 
1. I was at Mary's house yesterday. 
2. We talked about her brother. 
3. After 6 months of planning, he went to Alaska with 
two friends. 
4. Together, they made a successful assault on Denali. 
5. Mary was very proud of him. 
I find both examples a bit awkward, but nevertheless 
understandable. Accounting for TF movement in each of 
them is straightforward. However, whether to attribute the 
awkwardness of these examples to exceeding people's 
processing capabilities or to a problem with the theory is 
grist for further study. 
153 
5. Conclusion 
In this paper, I have given what I believe to be a 
credible account of the role that tense plays in the 
listener's reconstruction of the events and situations a 
speaker has chosen to describe. I have provided support 
for several new ideas: (a) that tense is better viewed by 
analogy with definite NPs than with pronouns; (b) that a 
narrative has a temporal focus that grounds the context- 
dependency of tense; and (¢) that focus management 
heuristics can be used to track the movement of temporal 
focus. I have also identified a host of problems that require 
further work, including (1) how to incorporate aspectual 
interpretation into the model, (2) how to evaluate 'strong 
associations' between events and/or situations and (3) 
how to judge plausibility. 
Acknowledgments 
I would like to extend my thanks to Debby Dahl, 
Martha Palmer and Becky Passonneau at UNISYS for 
their enthusiastic support and trenchant criticism. I have 
also gained tremendously from discussions with James 
Allen, Barbara Grosz, Erhard Hinrichs, Aravind Joshi, 
Hans Kemp, Ethel Schuster, Candy Sidner, and Mark 
Steedman. 
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