Time adverbials

Temporal relations are especially dependent for their expression upon time adverbials. Time adverbials convey temporal relations between the time they denote and the verbal event they syntactically depend on.

Time adverbials are syntactically realised by means of adverbs, noun phrases, prepositional phrases and temporal clauses. Most adverbs (e.g. yesterday), noun phrases (e.g. last week ) and prepositional phrases (e.g. on Monday) that

Figure 2.4: Reichenbach’s interpretation of the English tense – aspect system

express the semantic role of time are considered temporal expressions, and it should be noted that temporal expressions form the largest subclass of time adverbials. Temporal clauses (e.g. John came home after Mary left.) are another realisation of time adjuncts, a temporal clause being able to relate the time of the event it mentions to the time of the event described in the clause it syntactically depends on. While temporal expressions relate an event to a time, temporal clauses establish temporal relations between two events. The time of the event described in the main clause may be previous to, subsequent to, or

simultaneous with the time of the event described by the temporal clause. Section 2.3 has already described in detail the different types of time-related information TEs can convey: position, duration, frequency and relationship. These subroles also apply to all time adverbials, as one can see in their description below.

Time position adverbials

When expressing time position, time adverbials can narrowly pinpoint the exact time an event took place ([2.63]), or they can denote a wider time interval to which the event time belongs ([2.64]).

[2.63] Mary left at 10:30 am. [2.64] John went to India last year.

In both cases, time position adverbials refer to a span of time within which, at some point of time, the events took place. This applies to prepositional phrases introduced by on, at or in.

Prepositional phrases introduced by after or before place the time of the event denoted by the verb after, respectively before, the time denoted by the noun phrase following these prepositions.

Time position can also be expressed via temporal clauses. Temporal clauses introduced by when and as indicate the simultaneity of the events in the main and subordinate clauses, whereas subordinators like after, as soon as and once indicate that the event expressed in the main clause takes place after the event of the subordinate clause. The opposite effect is obtained by temporal clauses introduced by before, as they indicate that the event in the main clause happened before the one in the temporal clause.

Durative adverbials

Temporal duration can either be expressed as a general temporal measure, or the duration can be anchored either to a specific position on the time axis or to the time of an event.

Durations expressed using noun phrases and prepositional phrases introduced by the prepositions for indicate the fact that an event lasted the exact amount of time denoted by the durative expression.

Durations expressed by prepositional phrases introduced by during, within,

over, throughout indicate that the time of the event is included in the specified

time span. Similarly, temporal clauses introduced by while and whilst indicate that the time of the event in the main clause is included in the time span denoted by the durative clause they introduce.

In the case of the temporal subordinators as long as and so long as, both the main clause and the subordinate clauses are durative and these subordinators generally indicate that the situations begin and end at the same time, thus emphasising both simultaneity and duration.

Less specificity is encountered in the case of durative prepositional phrases introduced by prepositions like until, till, up to, and to.5 _{Such PPs indicate a time}

interval extending from a reference time point prominent in discourse to the point in time specified by the phrase in question. The temporal relation suggested in this case is that the event is bound by the specified temporal interval. The same applies to temporal clauses introduced by until and till, with the only difference consisting in the end point of the interval being specified as being the time of the event mentioned in the until/till-clause.

5. This statement applies to PPs introduced by to only when they are correlated with from- PPs (e.g. from December 1998 to June 2005 ).

Durative PPs introduced by the prepositions since and from indicate an interval starting from the point in time specified by the PP and ending at the reference time that is prominent at that point in the discourse. Temporal clauses introduced by since are in a similar position, indicating that the interval starts at the moment in time indicated by the since-clause.

Frequency adverbials

Time adverbials can also convey frequency, describing how often an event occurs. They are mostly realised by adverbs (e.g. weekly), noun phrases (e.g. every day), or temporal clauses introduced by whenever and in certain cases by when.

Frequency adverbials can express definite frequency (e.g. annually) or

indefinite frequency (e.g. usually), but in all cases they indicate a repetitive nature of an event with either a specified or unspecified frequency.

Temporal clauses introduced by whenever or when (when used to imply repetitiveness) may imply that the events of the main and of the subordinate clause overlap in time if at least one of the clauses is durative ([2.65]).

[2.65] Mary is careful whenever she crosses a street.

Time relationship adverbials

Time adverbials can express a relationship between two time positions that are both being considered in an utterance. They are typically realised by adverbs that signal temporal sequence, such as: afterwards, then, before, later, next, previously,

subsequently. They indicate the temporal relation that holds between the event

expressed by the verb they syntactically depend on, and the reference time point or the event that was last introduced in the preceding discourse.

This section has shown that time adverbials represent an important source of information in the process of inferring the temporal relations holding between events and temporal expressions. Since in most cases time adverbials are expressed using temporal expressions, the relations they typically provide are between the event expressed by the verb the adverbial depends on, and the temporal expression forming the adverbial. In the case of noun phrases and most adverbs in the role of a time adverbial, the temporal relation conveyed is one of simultaneity. For example, given the sentence [2.66], the event moved and the time adverbial last year are overlapping temporally. In the case of prepositional phrases and temporal clauses, the temporal relation is typically indicated by the preposition or the subordinator. In example [2.67] the subordinator after indicates that the event of moving is temporally after the event of graduating.

[2.66] Mary moved to France last year.

[2.67] Mary moved to France after she graduated.

In this thesis, all types of time adverbials will be automatically identified using first a methodology to identify time expressions (see Section 4.3 for more details), and then a different methodology targeting the identification of temporal clauses which is described in detail in Section 7.2.