Prepositions

There are three basic types of prepositional phrases, and three places at which they can adjoin. The three types of prepositional phrases are: Preposition with NP Complement, Preposition with Sentential Complement, and Exhaustive Preposition. The three places are to the right of an NP, to the right of a VP, and to the left of an S. Each of the three types of PP can adjoin at each of these three places, for a total of nine PP modifier trees. Table 20.1 gives the tree family names for the various combinations of type and location. (See Section 24.4.2 for discussion of the spuPnx, which handles post-sentential comma-separated PPs.)

	position and category modified
	pre-sentential	post-NP	post-VP
Complement type	S modifier	NP modifier	VP modifier
S-complement	Pss	nxPs	vxPs
NP-complement	Pnxs	nxPnx	vxPnx
no complement	Ps	nxP	vxP
(exhaustive)

{Preposition Anchored Modifiers

 

The subset of preposition anchored modifier trees in Figure 20.9 illustrates the locations and the four PP types. Example sentences using the trees in Figure 20.9 are shown in ((355))-((358)). There are also more trees with multi-word prepositions as anchors. Examples of these are: ahead of, contrary to, at variance with and as recently as.

Pss		nxPnx		vxP		vxPPnx

{Selected Prepositional Phrase Modifier trees: $\beta$Pss, $\beta$nxPnx, $\beta$vxP and $\beta$vxPPnx

 

(354)0(354

(355)

[_PP with Clove healthy _PP], the veterinarian's bill will be more affordable . (Pss^20.4)  (355)0(355

(356)

The frisbee [_PP in the brambles _PP] was hidden . (nxPnx)  (356)0(356

(357)

Clove played frisbee [_PP outside _PP] . (vxP)  (357)0(357

(358)

Clove played frisbee [_PP outside of the house _PP] . (vxPPnx) 

Prepositions that take NP complements assign accusative case to those complements (see section 4.4.3 for details). Most prepositions take NP complements. Subordinating conjunctions are analyzed in XTAG as Preps (see Section 16 for details). Additionally, a few non-conjunction prepositions take S complements (see Section 8.8 for details).