THE ANALYSIS OF TENSE AND ASPECT IN EUROTRA 
Frank VAN EYNDE 
Eurotra - Leuven 
Maria-Theresias~aat 21 
3000 Leuven 
BEI.~IUM 
ABSTRACT 
This papua plesel~ts a framework tot the modebfl~eoletic 
analysis of tense and aspect tonns in diseomse. It has been 
developed for Eurot~'a, the MT project of the Europeau 
Community, and has been applied to the nine Eurotra 
languages: English, German, Dutch, Danish, Greek, Italian, 
French, Spanish and Portuguese. 
The paper censis~s of six parts. The first presents the prob- 
lem of translating tense and aspect forms and indicates the 
type of solution I envisage. The second contains a formal- 
ism for tile. representation of time meanings. The third and 
the fourth present a theory of tense and aspect respectively. 
The fifth discusses the issue of compositionality and the 
sixth is at;out the use of the system in the Eurotra frame- 
work. 
1. THE PROBLEM 
It is a facL of language that the number and the use of the 
tense and aspect forms are different for every language. 
Even for closely related languages the differences teld to 
be large. As a consequence, it is not possible to state one- 
to-one conespondences between the tense and aspect forms 
of different languages. Some exanlples: 
EN he has lived in London for 20 years 
(presem perfect) 
FR. il vit ~t Londres depuis 20 aus 
(simple present) 
EN he has been watching TV for hours 
(pl~esent perfect progressive) 
PR il a regard6 la t616 pendant des heures 
(pl~esent perfect) 
Differenccg like these pose non-trivial problems for machine 
translation. In general there are two ways in which they 
can be handled : either by defining complex mappings from 
source lant;uage forms to target language forms in transfer 
SL folan .................. --~ TL form 
complex 
mappings 
or by defining mappings between language specific forms 
and interlingual meanings in the monoUngual components 
meaning .............. ~ meaning 
1" identity I 
mapping I I mapping 
i $ 
SL form TL form 
Because of Eurotra's policy to keep the bilingual transfer 
components as small and simple as possible it has been 
decided tc, pursue the interlingual approach. 
The resulting system is based on htsighls from 
- interval semantics (cf. Bennett, Partee, Dowty, Bruce) 
- the Reicheubachian analysis of tense and aspect in terms 
of time of speech, time of reference and time of event 
(cf. Reichenbach, Johr~von, Smith) 
- discourse representation theory (of. Kamp, Rohrer, Partee) 
- descriptive typological studies (cf. Comrie) 
2. THE FORMALISM 
As a starting point I take the temporal structure <T,<,ca>, 
where T is a set of intervals, < is a binary relation that 
linearly orders time (precedence), and n is a binary opera- 
tion on intervals (intersection). 
An interval is a continuous subpart of the time line (a). It 
may consist of one single moment of time (b), but it can- 
not contain any gaps (c): 
I I 
(a) ........ ~ (h) ........ * ..... ~ (c) ---~=--a--~::.-~-> 
The intersection of two intervals is that subpart of the 
intervals which they have in common: 
I J 
InJ 
Given the temporal structure <T,<,n>, the number of possi- 
ble relations between intervals can be determined in a prin- 
cipled way: for any ordered pair of intervals (I and J), it 
will be the case that 
either I ca J = O 
and then <(l,J) 
or >(I,J) 
I 
--~-~--~ (preceed) 
J 
I 
--~-~---> (follow) 
J 
or InJ¢:O 
andthen It~J=l and lnJ=J 
I 
=(I,J) ........ ~---~ 
J 
(identity) 
or InJ=l and lnJc:J 
I 
c(I',J) = --> 
J 
@art-of) 
o1" I ~ J ¢: I and I n J = J 
I 
~(l,J) .... ~----4 
J 
(inclusion) 
699 
or l c3 J :/:l and l ¢~ J ¢ J 
I 
<<(I,J) -.c:---~:-----d-~----zcn--~ 0eli 
J overlap) 
I 
>>(l,J) --rz=::=z=~=r~-:~-~--2z-a.--:~ (right 
J overlap) 
These are the seven logically possible relations between 
ordered pairs of intervals on a one-dimensional time line. 
For the analysis of single isolated clauses I will nse the 
Reichenbachian notions of time of speech, time of reference 
and time of event. The time of event (E) is tile interval 
for which a basic tenseless proposition is said to be true, 
and the function of the tense and aspect forms is to define 
the relation between that interval and the time of speech 
(S) via the intermediary time of reference (R.). 
For the analysis of clauses in context I make use of a gen- 
eralised model (cf. 3.4.). 
3. A THEORY OF TENSE 
3.1. file tense meanings 
Tense meanings will be defined as relations between a time 
of reference and a time of speech : Rel(R,S). 
The number of possible tense meanings is, hence, equal to 
the number of possible relations between R and S, which is 
seven (cf. 2.). However, since the time of speech is gen- 
erally conceived to be a moment of time rather than an 
interval of some length, some of these relations carmot hold 
in principle. The overlap-relations (<< and >>), for instance, 
can tufty obtain between two intervals of a certain length, 
and the proper part-of relation (c) cannot hold between R 
and S either, for if S is one moment of time, R can only 
be a proper part of S if it is smaller than a moment, 
which is impossible. 
Furthermore, there seems to be no linguistic evidence lot 
making a distinction between proper inclusion (w) and iden- 
tity (=), since "... languages do not have distinct grammatio 
eal categories of tense indicating location in time at a par-. 
ticular point vs. location in time surrounding a particular 
point." \[Comrie 1985, 123\] 
As a consequence, the number of possible relations between 
R and S can be reduced to the following three: 
<(R,S) = anteriority 
>(R,S) = posteriority 
~(R,S) = simultaneity 
These COlTespond to the traditional concepts of Past, Future 
and Present. Notice, however, that the latter is not defined 
in terms of identity, but in terms of improper inclusion. 
The language specific forms for the expl~ession of these 
concepts are the tense forms and the time adverbials. 
3.2. tire deictic time adverbials 
Typical examples of deictic time adverbials are "now", 
"tomorrow", and "two weeks ago". Their function is to 
relate the time of ~eference to the time of speech. Depend- 
ing on the kind of relation they express they can be 
charactefised as 
simultaneous : now ... 
anterior : yesterday, two weeks ago ... 
posterior : tomorrow, next summer ... 
7{30 
3.3. the tense forms 
In contrast to the tense meanings which are language 
independent the tense forms are langnage specilic. Their 
number, names and distribution differ from language to 
language. 
As h~r the Eumtra languages there seem to be two type~ of 
telJse fonn systems: the one of the Romance langllages v~M 
the one of the Germanic languages and Greek. 
An example of the latter type is English: 
tense form --~ \[+/.-ED\] (will+infinitiw;) 
yielding 
\[-ED\] ~ ,= lh~esent play 
\[+ED\] f3 = Past played 
\[uED\] will =: Future will play 
\[+ED\] will = Condilion~ would play 
There is a bound morpheme \[+/4~:D\] and an optional auxili-- 
ary "will". The latter can "also have a modal meaning, espe- 
cially in its past tense lonn, bnt in this context I will only 
discuss its temporal meaning. 
An examtfle of the former type is French: 
tensefo~m--~ \[\[+/-R\]\[+/-AIS\]\]Pass6 
yielding 
i-R\] \[-AIS\] = Pr6sent joue 
\[+R\] \[-AIS\] = Fntur jouerai 
i-R\] \[+AIS\] = Imparfait jouais 
\[+R\] \[+AIS\] = Conditionnel jouelais 
Pass6 = Pass~ jouai 
In this system the tense forms are combinations of bound 
moq)heines; there are no anxiliaries involved. 
As for the meanings of the tense forms they will be 
defined as elements of the power set of possible tense 
meanings. This power set contains eight elements : 
{~, {<), {>), (~}, {<,>1, (<,_~}, (>,~l, 1<,>,~}). 
Not all of these combinations can be assigned to particular 
lense forms, though, for there are a few general constraints. 
Bernard Comrie has argued, lbr instance, that "in a tense 
system, the time reference of each tense is a continuity" 
\[Comrie 1985, 50\]. This implies that there can be no tense 
lbm~s which can express posteriority and anteriority without 
expressing simultaneity as welt. The combination {ante,post} 
can, hence, be discarded a priori. For the Eurotra languages 
this restficition appears to hold. 
A second restricition concerns tile combinatiotts {ante,simnl} 
and {post,simul}. The former is a possible me,'ming in 
languages which make a basic distinction between Future 
({post}) and non-Fut~e ({ante,simul}) ; the latter is a pos- 
sible meaning in languages which make a basic distinction 
between Past ({ante}) and non-Past ({post,simul}). Since a 
h'mguage cam~ot belong to both types at the same time, it 
follows that for any given langnage either file contbination 
{post,simul} or the combination {ante,simld} is rnl~ out. 
As far as the Enrotra languages are concerned, they all 
belong to the latter type. 
In older to find out wtfieh of tile six remaining combina. 
tions can he assigned to file tense forms one can make nse 
of a grammatie,'dity test : a tense from X can have a 
meaning Y (where Y is any of {simultaneous, anterior, pos- 
terior}), if and only if it can be combined with a deictic 
adverbial of type Y. 
The application of this test to English 
the following results : 
Er~glish : 
and French yields 
French : 
Present -4 {post,simul} 
Past ~-~ {~nte} 
Future ~ {post} 
Conditional ~-~ 0 
PrEsent ~ {post,simul } 
Futur ~ {post} 
lmparfalt --~ {ante} 
Condifionnel --~ 0 
Pas~ --o { ante } 
The conditional tenses get the value O since they do not 
have a temporal meaning in single isolated clauses (cf. 
3.6.). 
3.4. a discourse model 
The model presented so far is useftd for the analysis of 
isolated clauses. For tl~e analysis of texts we need an 
extension, or rather a generalisation of the original model. 
The main extensions concern the introduction of another 
kind of interval, the point of perspective P (the term is 
bon~wed from \[Rohrer 1985\]), and the addition of indices 
to the intervals. 
Instead of defining the time of reference with respect to the 
time of speech I will now define its position with respect 
to the point of perspective. For any clanse i which is part 
of a discourse, there will be one peint of perspective Pi 
and one time of reference Ri. If the clause is the lirst main 
clause of the discourse, then its point of perspective is 
derived from the time of speech. In other cases the point 
of perstx~'ctive will be, derived fl~m tile time of reference of 
a dominating or preceding clause. 
An example: 
R0 ANCHORING TENSE 
(1) V she R1 
promisedthat ~-~ ...... pie-.--) V(PI,R0) & <(RI,I'1) 
she would V R2 
come on __,...~7~ ...... --_) V(P2,R1) & >(R2,P2) 
Monday P2 V R2=Monday 
but she R3 
lnmed up .......... ...i7z3__~ V(P3,R2) & >(R3,P3) 
2 days P3 R3=Wednesday 
later 
The notation "V(Pi,Rjy means that Pi is derived from Rj. 
The interval Rj from wlfich the pesition of Pi is derived 
will be called the temporal antecedent of the clause with 
point of perspective Pi. In the example the temporal 
antecedent of the third clause is "Monday" (R2), the tem- 
poral antecedent of the second clause is the time of her 
promising (R1), and the temporal antecedent of the first 
clause is the lime of speech (R0=S). 
Notice that file temporal antecedent of a clause i need not 
always be the time of reference of the immediately preced- 
ing clau,~:e (Ri-1). In the sequence 
(2) she promised that she would come on Monday, but 
then she changed her mind 
the temporal antecedent Of the third clause is the thne of 
her prondsing (R1) rather than "Monday", and in 
(3) she promised that she would come on Monday, but 
now it seems that she cannot 
the temporal antecedent of the third clause is the time of 
speech : "now" refers back to the time of speech directly. 
The differences between the discourse model and the origi- 
nal temporal model are minor: the tense meanings are now 
relations between Ri and Pi (instead of between R and S) 
but, since Pi is always a moment of lime (just like S), the 
number of possible tense meanings remains the same. The 
expressive power of the tormalism, however, has been 
enhanced considerably. It now provides a formalism lbr 
the temporal analysis of all types of clauses - whether 
enrbedded or not, whether isolated or in context - and for 
the description of anaphoric temporal expressions. The latter 
will be discussed in the next paragraphs. 
3.5. the anaphorie time adverbials 
There is a class of adverbials which do not refer to the 
time of speech, as the deictie ones, but rather to the time 
of relerence of a dominating or preceding clause. They can 
also be grouped in the three subclasses 
simultan : the same time, at that moment ... 
anterior : two weeks before, previously ... 
posterior : one week later, then ... 
Together with the deictic adverbials they form the class of 
relational time adverbials. 
For completeness sake I 'also mention the locational time 
adverbials, such as "at 2 o'clock", "on Monday" and "in 
the summer". They do not express any relational informa- 
tion and can, therefore, be combined with all possible 
tcoses. 
Common to both the relational and the locational time 
adverbials is that they can be used as ,answers to "when"- 
questions. In this respect they differ from the a.';pectual 
adverbials (cf. 4.3.). 
3.6. anaphoric tenses 
The use of the tense forms in texts is somewhat different 
from their use in single isolated clauses. This is due to the 
fact that in anterior contexts the present is often replaced 
by file past and the future by the conditional. This 
phenomenon, which is called transposition (of. Rohrer 
1985), can be seen at work in the following sentences: 
(4) he said that he was ill 
(5) he entered the room and fell on his face 
In (4) tbe time of Iris being ill is simultaneous with his 
saying that he is ill, and in (5) the time of his falling on 
his face is posterior to the time of his entering the room. 
In both cases one would expect a present tense in the 
second clause, bnt since the first clause is in the past, tran- 
sposition applies and results in the use of the past tense. 
Tfie discourse diagrams for these sentences look as follows: 
701 
R0=S 
(4)' ! V he said R1 
that ......... 1--~ 
hewas 
iU ~ ..... -~ 
P2 
ANCHORING TENSE 
V(PI,RO) & <(R1,P1) 
V(P2,R1) & ~(R2,P2) 
R0=S 
(5) V~ 
he entered R1 
the room -~-- ....... P1 
and fell 
on his R2 
face ..... ,...m=-=t_.__~ 
P2 
V(P1,R0) & <(RI,P1) 
V(P2,R1) & >(R2,P2) 
Similar remarks can be made about the use of the condi- 
tional in 
(6) we all hoped that he would soon recover 
From the point of view of analysis there are at least two 
ways of dealing witb the phenomenon of transposition: it 
can be treated as a syntactic transformation or as an irregu- 
larity in the relation between form and meaning. In the 
former case one first maps the past on the present and the 
conditional on the future and then applies the normal rules 
for the assignment of meanings. In the latter case one 
defines extra rules for the assignment of meanings to the 
past and the conditional tenses. 
The former alternative is more constrained than the latter 
and, hence, more attractive, but the choice for the one or 
the other might turn out to be language dependent. 
4. A THEORY OF ASPECT 
4.1. the aspect meahings 
There is a considerable confusion in the literature about the 
definition of aspect. This is largely due to the fact that 
many authors donot make a distinction between grammatical 
aspect and lexical aspect. The former concerns the syntax 
and semantics of aspectual auxiliaries and adverbials, 
whereas the latter concerns the semantics of main verbs and 
propositions (cf. the event/state/process distinction). In this 
paper I will use the term aspect for the former only. The 
latter will be called Aktionsart. 
As a general definition of aspect I will adopt the formula- 
tion by Marion Johnson: "What I am proposing concerning 
the semantiCS of the aspect forms is that they specify the 
relation between reference time and event time in an utter- 
ance." \[Johnson 1981, 153\] 
Starting from this definition of aspect meanings as binary 
relations between intervals and combining it with the obser- 
vation that the number of possible binary relations between 
intervals is seven (of. 2.) it is possible to predict that there 
will be seven aspectual relations. In the following para- 
graphs I will discuss them in some detail and relate them 
to the traditional aspectological terminology. 
A well-known aspectual distinction is the one between the 
perfective and the imperfective. The perfective presents a 
situation as a single unanalysable whole, whereas the imper- 
fective looks at a situation from the inside and focusses on 
the beginning, ending or continuation of it (el. Comrie 
1976, 3-4). 
As formal counterparts of these definitions I propose the 
relations =(E,R) and c(E,R) for the perfective : 
702 
E ~E 
R R 
E E 
...... -EEEE~---~ ---~-~ 
R R 
These relations express the intuition that ti~ time of event 
(E) is seen as one unanalysable whole from the point of 
view of the reference time. The formal definition of the 
perfective is, hence, ~(E,R). 
For the imperfoctive I will make a distinction between three 
types. If the focus is on the continuation, the aspect is 
durative. For its representation I use the relation of proper 
inclusion : D(E,R). 
E E 
R R 
The situation is clearly looked at from the inside : R is in 
E. 
For the two other types of imperfectivity I will make use 
of the overlap relations : 
E E 
.~F-'272~...~ . .t-Z'YY77&L......ZZS.T -.q, 
R R >>(E,R) <<0~,R) 
In the ease of right overlap the focus is on the beginning 
of the situation. This aspect I will call the inchoative. In 
the case of left overlap the focus is on the end of the 
situation. This aspect I will call the terminative. 
Another aspect that is often mentioned in the literature is 
the socalled perfect (# perfective !). In conformity with 
Reichenbach, Johnson and others I will analyse it in terms 
of precedence : <(E,R). I will, however, not use the term 
"perfect" for it, but rather the term "retrospective". The rea- 
son for this is that the perfect aspect form should be dis- 
tingnished from the retrospective aspect meaning : the 
former is syntactic, the latter is semantic, and the relation 
between both is not necessarily one-to-one. 
Finally, there is the inverse of the retrospective, i.e. the 
prospective : >(E,R). It is one of the meanings of the 
English "be going to" and of the French auxiliary "aller". 
In short, there are six different aspect meanings. Their 
language specific counterparts are aspeetual auxiliaries and 
adverbials. 
4.2. the aspectual auxiliaries 
As for the Eumtra languages the aspect form systems show 
a larger diversity than the tense form systems. 
Some typical aspectual distinctions are the ones between 
- perfect and non-perfect (have + past participle) 
- progressive and non-progressive (be + present participle) 
- go and non-gu (go + to-infinitive) 
The first distinction is made in all of the Eumtm languages, 
but the two other ones are not eumversal. They are present 
in English, but not ha German and Danish, for instance, 
and French has the third distinction, but not the second. 
It may be worth stressing that I will only analyse the 
aspectaal anxiliaries. Full lexical verbs, such as "stop", 
"start" and "continue", and periphrastic forms, such as "~tre 
en train de" and "venir de", will not be discussed here. 
l?br English, the set of aspectual auxiliaries can be defined 
as follows: 
aspect 
O ¢5 
have O 
f~ be 
have be 
O be 
have be 
l;br French, 
aspect 
lonn --) (have+papa) (be+prpa(go+to-int)) 
f~ = Simple rain 
O = Perfect have rained 
O = Progressive be mining 
O =Perf Progr have been raining 
go = Go be going to rain 
go = Perfect Go have been going to rain 
the definition looks as follows : 
lbrm --> \[ avoir/~tre+papaaller+inf \] 
O = Simple pleuvoir 
avoir/~tre = Compost avoir plu 
aller = Futur proche aller pleuvoir 
As tor the assignment of meanings to the auxiliaries I will 
follow the same procedure as for the tense meanings. The 
meaning of an aspect form is an element of the power set 
of possible aspect meanings. This set contains 64 elements. 
For the dr;fruition of the mappings one can start from the 
following euroversal scheme (euroversal = common to the 
nine Eurotra languages) : 
simple -~ {perfective} 
perfect --> {retrospective} 
go ~ {inchoafive} 
progressive -~ {durativc} 
If one of these tbrms is not present in the language, its 
meaning may he expressed by another form. In general this 
will be the form whose basic meaning is the least distant 
from the meaning to be expressed. For a specification of 
the notion of distance between meanings I will use the fol- 
lowing scheme: 
retm term perf, dur incho pro 
< << .~ , =3 >> > 
1 2 3 4 5 
The distance between two ,aspect meanings is equal to the 
difference of their numbers. 
it follows frmn the principle of minimal distance that a 
language without a progressive will express the durative by 
means of the form which expresses the perfective (13-31=0), 
i.e. the simple form. This is indeed tree for French, 
Dutch, German and Danish. 
Tbe principle also guides the choice of a form for the 
expression of file terminative. Some languages have a spe- 
cial form for this aspect. English, for instance, has the per- 
\[izct progrcssive for this meaning. Most languages, however, 
donot have such a tbrm and in those cases the minimal 
distance principle predicts which forms can be used for the 
expression of terminativity, i.e the (retrospective) perfect 
lbrm, the (perfective) simple form or the (durative) progres- 
sive foim: 12.-11=12-31=1 (see also 4.3.). 
Taking into account the basic scheme and the principle of 
minimal distance, ,and complementing it with language 
specific observations, one can derive the following mappings 
for English and French: 
English : 
French : 
Simple --> {pelf} 
Perfect --~ {retro,term} 
Progressive ~ {dur,perf} 
Perf progr --~ {term} 
Go ~ {incho,pro } 
Perfect Go --4 O 
Simple --~ {perf,dur,term } 
Compost ~ { retro,tenn } 
Futur proche ~ {incho,pro} 
4.3. aspectual adverbials 
Tile aspectual adverbials include the duration adverbials and 
the boundary adverbials. 
The duration adverbials specify the length of the time of 
event. Depending on whether the basic proposition is an 
event or a state/process they are expressed by an 1N- 
adverbial or a FOR-adverbial: 
(7) she ran the mile in five minutt~ 
(8) he has been sleeping for ten hours 
(9) we have been in France for a month 
They do not express any relational information. 
The boundary adverbials specify the beginning and/or the 
end of the time of event. They are prepositional pbrases 
introduced by "since", "from", "until", "till", "from .. till". 
One of these expresses relational information: the "since"- 
adverbials denote an interval which begins in the past at 
some specified time, e.g. Christmas in "since Chrismlas". 
The end point of such an interval is not specified by the 
adverbial, but is normally taken to be included in the time 
of reference. The relation between time of event and time 
of reference will, hence, be one of overlap: 
E 
Xmas R 
It tbllows that "since" adverbials express terminativity and 
that the compatibility of these adverbials with the aspect 
forms can be used as a test for deciding whether a given 
aspect form can be terminative. 
What the aspectual adverbials have in common is that they 
can be used as answers to "how long"-questions. This dis- 
tinguishes them from the time adverbials. 
5. DEGREES OF COMPOSITIONALITY 
Tense and aspect forms do not occur in isolation: finite 
verbs have both a tense form and an aspect form. The 
meaning of their combination is the relational product of 
the meanings of the tense form and the meanings of the 
aspect form. An example: the meaning of the English 
present perfect progressive is the relational product of the 
meanings of the present tense with the meanings of the 
perfect progressive aspect. In other words, the meaning of 
the present perfect progressive is compositional. 
Not all combinations of tense and aspect are compositional, 
though. In some cases a form can have a meaning which 
cannot be derived eompositionally, in other cases a form 
may lack a meaning which can be derived compositionally. 
703 
An 'example of the former type is the present perfect in 
languages like French, Dutch and German. Apart from or 
even instead of its compositional meanings this form has an 
<anterior, peffective> meaning, i.e. the meaning of the 
English simple past. This appears a.o. from their compatibil- 
ity with anterior time adverbials: 
FR je l'ai vu bier 
DU ik beb hem gisteren gezien 
GE ich habe ihn gestem gesehen 
EN * I have seen him yesterday 
I saw him yesterday 
An example of the latter type is the French passd simple. 
The simple aspect can have three different meanings in 
French, but in combination with the passg, it can only have 
the perfective interpretation: the durative and the terminative 
meaning are expressed by the imparfait. 
Depending on how many exceptions there are, the tense 
and aspect system of a given language will be more or less 
compositional. In ease of a low degree of compositionality 
one could decide to assign meanings to combinations of 
tense and aspect forms, rather than to tense and aspect 
forms separately. 
6. THE SYSTEM IN USE 
Eurotra is a transfer based system. The integration of the 
given analyses in the Eurotra framework has been achieved 
as follows. 
In analysis the tense and aspect forms are mapped onto 
their meanings. This mapping is many-to-many and will, 
hence, result in the assignment of many meanings to one 
and the same form. Disambiguation is done on the basis 
of the context. Factors to be taken into account are the 
temporal adverbials and the Aktionsart of the basic proposi- 
tion. 
In transfer the tense and aspect meanings are simply 
copied: their representations are interlingual. 
In generation the meanings are mapped onto forms. Unlike 
the mapping in analysis, this mapping is a function. 
The system presented in this paper has been applied to the 
nine Eurotra languages and has been implemented in terms 
of the unification based Eurotra formalism. Still lacking at 
this moment are the treamaent of the transposed uses of the 
tenses and the rules for determining the Aktionsart of basic 
propositions. 

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