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Time Noun Phrases

Although in general NPs cannot modify clauses or other NPs, there is a class of NPs, with meanings that relate to time, that can do so.20.3 We call this class of NPs Time NPs''. Time NPs behave essentially like PPs. Like PPs, time NPs can adjoin at four places: to the right of an NP, to the right and left of a VP, and to the left of an S. Time NPs may include determiners, as in this week in example ((348)), or may be single lexical items as in today in example ((349)). Like other NPs, time NPs can also include adjectives, as in example ((353)).
(347)0(347
(348)
Elvis left the building this week  (348)0(348
(349)
Elvis left the building today  (349)0(349
(350)
It has no bearing on our work force today (WSJ)  (350)0(350
(351)
The fire yesterday claimed two lives

(351)0(351
(352)
Today it has no bearing on our work force  (352)0(352
(353)
Michael late yesterday announced a buy-back program

The XTAG analysis for time NPs is fairly simple, requiring only the creation of proper NP auxiliary trees. Only nouns that can be part of time NPs will select the relevant auxiliary trees, and so only these type of NPs will behave like PPs under the XTAG analysis. Currently, about 60 words select Time NP trees, but since these words can form NPs that include determiners and adjectives, a large number of phrases are covered by this class of modifiers. Corresponding to the four positions listed above, time NPs can select one of the four trees shown in Figure 20.4.

 Ns Nvx vxN nxN

{Time Phrase Modifier trees: $\beta$Ns, $\beta$Nvx, $\beta$vxN, $\beta$nxN

Determiners can be added to time NPs by adjunction in the same way that they are added to NPs in other positions. The trees in Figure 20.5 show that the structures of examples ((348)) and ((349)) differ only in the adjunction of this to the time NP in example ((348)).

{Time~NPs with and without a determiner

The sentence

(353)0(353
(354)
Esso said the Whiting field started production Tuesday (WSJ)

has (at least) two different interpretations, depending on whether Tuesday attaches to said or to started. Valid time NP analyses are available for both these interpretations and are shown in Figure 20.6.

& &

{Time~NP trees: Two different attachments \label{esso

Derived tree structures for examples ((350)) - ((353)), which show the four possible time NP positions are shown in Figures 20.7 and 20.8. The derivation tree for example ((353)) is also shown in Figure 20.8.

& & -.55in

{Time~NPs in different positions ($\beta$vxN, $\beta$nxN and $\beta$Ns) \label {bearingtrees

{Time~NPs: Derived tree and Derivation ($\beta$Nvx position)

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XTAG Project
http://www.cis.upenn.edu/~xtag