Conjunction and gapping

Ordinary conjunction

In the basic schema for conjunction, shown below, the conjuncts themselves are labelled in the ordinary way. Second and subsequent conjuncts are enclosed by CONJP, and the entire conjunction structure is additionally labelled with the category of the first conjunct. The top-level label bears dash tags if appropriate; the lower labels don't. 

( (LABEL-1 (LABEL-1 ...)
	   (CONJP (CONJ conjunction)
		  (LABEL-2 ...))
	   (CONJP (CONJ conjunction)
		  (LABEL-3 ...))))

By default, conjuncts are phrases. For exceptions, see Head-level conjunction. 

( (NP (NP (D a)
	  (N house))
      (CONJP (CONJ and)
             (NP (D a)
		 (N car)))))

( (PP (PP (P to)
	  (NP (NPR California)))
      (CONJP (CONJ and)
             (PP (P to)
		 (NP (N-COMP (NPR New) (NPR York)))))))

( (IP-IMP (VP (VP (VBI Love)
                  (NP-OB1 (PRO it)))
	      (CONJP (CONJ or)
		     (VP (VBI leave)
			 (NP-OB1 (PRO it)))))
	  (PUNC .)))

In particular, even single-word conjuncts conjoin at the phrasal level, provided they are not head-level conjuncts. 

( (NP (NP (NPR Eva))
      (CONJP (CONJ and)
             (NP (NPR Tina)))))

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (VP (VBD (VBP come)))
	      (CONJP (CONJ and)
		     (VP (VBP go))))
	  (PUNC .)))

( (ADVP-LOC (ADVP (ADV here))
	    (CONJP (CONJ and)
		   (ADVP (ADV there)))))

Conjuncts are generally of the same syntactic category, but conjunction of unlike categories is also possible. 

( (ADJP (ADJP (ADJ dishonest))
        (CONJP (CONJ and)
	       (NP (D a)
		   (N thief)))))

( (NP (NP (D a)
	  (N thief))
      (CONJP (CONJ and)
	     (ADJP (ADJ dishonest)))))

( (ADVP (CONJ either)
	(ADVP (ADV here))
	(CONJP (CONJ or)
	       (PP (P at)
		   (NP (D the)
		       (ADJP (ADJ other))
		       (N house))))))

( (PP (CONJ either)
      (PP (P at)
	  (NP (D the)
	      (ADJP (ADJ other))
	      (N house)))
      (CONJP (CONJ or)
	     (ADVP (ADV here)))))
Recursive conjunction structures are possible. 
( (NP (NP (NP (NS apples))
	  (CONJP (CONJ and)
		 (NP (NS oranges))))
      (PUNC ,)
      (CONJP (NP (NP (NS beans))
		 (CONJP (CONJ and)
			(NP (NS peas)))))
      (PUNC ,)
      (CONJP (CONJ and)
	     (NP (NP (N coffee))
		 (CONJP (CONJ and)
			(NP (N tea)))))))

Head-level conjunction

Conjunction structures in which none of the conjuncts projects a phrase in our system are annotated to the following schema: 
( (LABEL-1 (LABEL-1 word) (CONJ conjunction) (LABEL-2 word)))

( (NP (D (D this) (CONJ or) (D that))
      (N answer)))

Head-level conjunction is also used to annotate structures in which otherwise bare heads share a syntactic dependent. For heads that are not bare apart from the shared syntactic dependent(s), see Shared modifiers, especially Shared post-modifiers. 

( (PP (P (P to) (CONJ and) (P from))
      (NP (N work))))

( (VP (VB (VB make) (CONJ or) (VB break))
      (NP-OB1 (D the)
	      (N deal))))

( (VP (VBD (VBD lived) (CONJ and) (VBD died))
      (ADJP-SPR (ADJ sober))))

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (ADVP (ADV repeatedly))
	      (VBD (VBD opened) (CONJ and) (VBD closed))	
	      (NP-OB1 (D the)
		      (N door)))
	  (PUNC .)))

As with ordinary conjunction, head-level conjuncts can bear different labels. (In most cases of head-level conjunction, the difference between conjoining like and unlike categories is an artefact of our labelling conventions rather than reflecting true conjunction of unlike categories.) 

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (MD will)
	      (VP (GT (GT get)
		      (CONJ and)
		      (VB keep))
		  (NP-OB1 (NP-POS (PRO$ their))
			  (N raise))))
	  (PUNC .)))

In the absence of overt conjunctions and the CONJP that delimits conjuncts in ordinary conjunction, silent conjunctions are added for clarity. 

( (PP (P (P over)
	 (PUNC ,)
	 (CONJ 0)
	 (P around)
	 (PUNC ,)
	 (PUNC ,)
	 (CONJ and)
	 (P under))
      (NP (D the)
	  (N desk))))
Particles. Particles present a special case because they sometimes fail to project a PP. When one bare particle conjoins with another, the structure is treated as head-level conjunction. In all other cases, the particle projects a PP, and the conjunction structure instantiates ordinary conjunction. 
( (VP (VB wander)
      (RP (RP to) (CONJ and) (RP fro))))		← assimilated to head-level conjunction

( (RP (RP in)
      (PUNC ,)
      (CONJ 0)						← silent CONJ delimits head-level conjunct
      (RP through)
      (PUNC ,)
      (PUNC ,)
      (CONJ and)
      (RP out)))

( (VP (VB step)
      (PP (PP (RP out))					← conjunction of like categories
	  (CONJP (CONJ and)
		 (PP (P into)
		     (NP (D the) (N rain)))))))

( (VP (VB step)
      (PP (PP (RP out))					← conjunction of unlike categories
	  (CONJP (CONJ and)
		 (ADVP (ADV away)
		       (PP (P from)
			   (NP (N danger))))))))

Silent CONJ

In the absence of an overt conjunction, silent CONJ heads may be added for clarity, but are not always explicitly indicated (as noted in Known issues). 

( (ADJP (ADJP (ADJ small))
	(PUNC ,)
        (CONJP (CONJ 0)				← explicit CONJ
	       (ADJP (ADJ medium)))
	(PUNC ,)
        (CONJP (CONJ and)
	       (ADJP (ADJ large)))))

( (ADJP (ADJP (ADJ red))
	(PUNC ,)
        (CONJP (ADJP (ADJ white)))		← implicit CONJ
	(PUNC ,)
        (CONJP (CONJ and)
	       (ADJP (ADJ blue)))))

Correlative conjunction

In correlative conjunction (BOTH ... AND, EITHER ... OR, NEITHER ... NOR), the first conjunction explicitly marks the left edge of the conjunction structure. The left edge marker is the first daughter of the node dominating the entire conjunction structure. 
( (NP (CONJ both)
      (NP (N coffee))
      (CONJP (CONJ and)
             (NP (N tea)))))

( (ADJP (CONJ either)
        (ADJP (ADJ red))
	(CONJP (CONJ or)
	       (ADJP (ADJ blue)))))

( (PP (CONJ neither)
      (PP (P inside)
	  (NP (D the)
	      (N house)))
      (CONJP (CONJ nor)
	     (ADVP (ADV outside)
	     	   (PP (P in)
		       (NP (D the)
			   (N yard)))))))

Negation, ALSO, and so on

NOT (ONLY)

NOT (ONLY) attaches as a daughter of the conjunct it is construed with (unlike ALSO). 

( (NP (NP (NEG not)
	  (FP only)
	  (N coffee))
      (PUNC ,)
      (CONJP (CONJ but)
	     (NP (N tea)))))

( (NP (NP (N coffee))
      (PUNC ,)
      (CONJP (CONJ and)
	     (NP (NEG not)
		 (FP only)
		 (N tea)))))

ALSO

ALSO attaches as a sister of the conjunct it is construed with (unlike NOT (ONLY)). 
( (NP (NP (N coffee))
      (CONJP (CONJ and)
             (ADVP (ADV also))
	     (NP (N tea)))))

Other (short) adverbial expressions that intervene between a conjunction and a non-first conjunct are treated analogously. 

( (NP (NP (N coffee))
      (CONJP (CONJ and)
             (ADVP (ADV perhaps))
	     (NP (N tea)))))

( (NP (NP (N coffee))
      (CONJP (CONJ and)
             (ADVP (ADV perhaps))
             (ADVP (ADV also))
	     (NP (N tea)))))

Shared modifiers

Shared pre-modifiers

When the first conjunct in a conjunction structure dominated by (W)ADJP, (W)ADVP, (W)NP or (W)NUMP includes pre-head material, the structure is annotated as follows. The entire conjunction structure is enclosed by the phrasal category for the first conjunct. The first conjunct itself is not surrounded by phrasal brackets of its own. Second and subsequent conjuncts are enclosed by ADJX, ADVX, NX, or NUMX, as appropriate. 
( (NP (ADJP (ADJ great))
      (N sorrow)
      (CONJP (CONJ and)
	     (NX (N grief)))))

( (NP (D an)
      (ADJP (ADVP (ADV extremely))
	    (ADJ happy)
	    (CONJP (CONJ and)
		   (ADJX (ADJ joyous))))
      (N occasion)))

( (NP (NUMP (ADVP (ADV barely))
	    (NUM five)
	    (CONJP (CONJ or)
		   (NUMX (NUM six))))
      (NS instances)))

( (WADJP (WADVP (WADV however))
	 (ADJ important)
	 (CONJP (CONJ or)
		(ADJX unimportant))))

( (WNP (WD whichever)
       (N car)
       (CONJP (CONJ or)
	      (NX truck))))

Shared post-modifiers

Shared post-modifiers in conjunction structures attach as high as possible - that is, as a daughter of the phrase dominating the entire conjunction structure. 

( (NP (NP (D the)
	  (N mother))
      (CONJP (CONJ and)
	     (NP (D the)
		 (N grandmother)))
      (PP (P of)
	  (NP (D the)
	      (N bride)))))

( (NP (D the)
      (N mother)
      (CONJP (CONJ and)
	     (NX (N grandmother)))
      (PP (P of)
	  (NP (D the)
	      (N bride)))))

( (VP (VP (VAG drinking)
	  (NP-OB1 (NS espresso)))
      (CONJP (CONJ and)
	     (VP (VAG eating)
		 (NP-OB1 (NS croissants))))
      (ADVP-TMP (ADV early)
		(PP (P in)
		    (NP (D the)
			(N morning))))))

Clausal conjunction

Conjunction of subordinate clauses

In general, clausal conjunction is governed by the guidelines discussed above. In particular, this is true for all subordinate CPs and IPs. By default, subordinate clauses are conjoined at the IP level. In other words, they are conjoined at the CP level only if non-initial conjuncts contain overt CP material, such as a wh- phrase or a complementizer. 
( (IP-MAT (NP-SBJ (PRO They))
	  (VP (VBD said)
	      (CP-THT (CP-THT (C-THT 0)
			      (IP-SUB (NP-SBJ (PRO he))
				      (VP (BED was)
					  (VP (VAG coming)))))
		      (CONJP (CONJ and)
			     (CP-THT (C-THT that)		← CP conjunction licensed by overt THAT

				     (IP-SUB (NP-SBJ (PRO she))
					     (VP (BED was)
						 (VP (VAG leaving))))))))
	  (PUNC .)))

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (VBD said)
	      (CP-THT (C-THT that)
		      (IP-SUB (IP-SUB (NP-SBJ (PRO he))		← IP conjunction
				      (VP (BED was)
					  (VP (VAG coming))))
			      (CONJP (CONJ and)
				     (IP-SUB (NP-SBJ (PRO she))
					     (VP (BED was)
						 (VP (VAG leaving))))))))
	  (PUNC .)))

Token-initial conjunction

Conjunctions introducing sentence tokens (see Division into sentence tokens for what counts as a sentence token) are treated as bare daughters of the matrix clause, rather than as projecting a CONJP. 
( (IP-MAT (NP-SBJ (PRO We))
	  (VP (VBD drove)
	      (PP (P to)
		  (NP (NPR Florida))))
	  (PUNC ,)))

( (IP-MAT (CONJ and)				← clause-initial bare CONJ
	  (ADVP-TMP (ADV then))
	  (NP-SBJ (PRO we))
	  (VP (VBD drove)
	      (ADVP-DIR (ADV back)))
	  (PUNC .)))




( (IP-MAT (NP-SBJ (PRO He))
          (VP (VBD said)
	      (PUNC ,)
	      (QTP (IP-MAT (NP-SBJ (PRO We@))
			   (VP (MD @'ll)
			       (VP (VB drive)
				   (PP (P to)
				       (NP (NPR Florida))))))))
	  (PUNC ,)))

( (QTP (IP-MAT (CONJ and)			← clause-initial bare CONJ
	       (ADVP-TMP (ADV then))
	       (NP-SBJ (PRO we@))
	       (VP (MD @'ll)
		   (VB (VB drive)
		       (ADVP-DIR (ADV back)))))
       (PUNC .)))




( (CP-QUE-MAT (CONJ But)			← clause-initial bare CONJ
              (WADVP-1 (WADV Why))
	      (IP-SUB (MD would)
		      (NP-SBJ (PRO they))
		      (VP (ADVP *T*-1)
			  (DO do)
			  (NP-OB1 (D a)
				  (N thing)
				  (PP (P like)
				      (NP (D that))))))
	      (PUNC ?)))

Shared clausal modifiers

Because matrix clauses constitute separate sentence tokens, modifiers shared by conjoined matrix clauses must be annotated as belonging to one clause or the other. As a result, clause-initial adjuncts appear as constituents of the first conjunct only, while clause-final adjuncts appear as constituents of the second conjunct only. 
( (IP-MAT (CP-ADV (C After)
		  (IP-SUB (NP-SBJ (PRO he))
			  (VP (VBD realized)
			      (NP-OB1 (NP-POS (PRO$ his))
				      (N mistake)))))
	  (PUNC ,)
	  (NP-SBJ (PRO he))
	  (VP (VBD turned)
	      (ADVP (ADV around)))
	  (PUNC ,)))

( (IP-MAT (CONJ and)
	  (NP-SBJ (PRO he))
	  (VP (VBD apologized))
	  (PUNC .)))




( (IP-MAT (NP-SBJ (PRO He))
	  (VP (VBD turned)
	      (ADVP (ADV around)))
	  (PUNC ,)))

( (IP-MAT (CONJ and)
	  (NP-SBJ (PRO he))
	  (VP (VBD apologized)
	      (PUNC ,)
	      (ADVP-TMP (ADVR as)
			(ADV soon)
			(CP-CMP (WADVP-1 (WADV 0))
				(C as)
				(IP-SUB (NP-SBJ (PRO he))
					(VP (ADVP-TMP *T*-1)
					    (VBD realized)
					    (NP-OB1 (NP-POS (PRO$ his))
						    (N mistake)))))))
	  (PUNC .)))

Shared clausal arguments

Very rarely, two matrix clauses that would ordinarily constitute separate tokens share a syntactic argument. The two clauses are then exceptionally treated as a single sentence token. 
( (IP-MAT (IP-MAT (NP-1 (D This)
			(N candidate))
		  (PUNC ,)
		  (NP-SBJ (PRO he))
		  (VP (VBP admires)
		      (NP-OB1 *ICH*-1)))
	  (PUNC ,)
	  (CONJP (CONJ and)
		 (IP-MAT (NP-SBJ (PRO she))
			 (VP (VBP detests)
			     (NP-OB1 *ICH*-1))))
	  (PUNC .)))

The same difficulty does not generally arise in connection with shared arguments in subordinate clauses. 

( (NP (D a)
      (N candidate)
      (CP-REL (WNP-1 (WPRO 0))					← argument shared across IP-SUBs
	      (C that)
	      (IP-SUB (IP-SUB (NP-SBJ (PRO he))
			      (VP (VBP admires)
				  (NP-OB1 *T*-1)))
		      (PUNC ,)
		      (CONJP (CONJ and)
			     (IP-SUB (NP-SBJ (PRO she))
				     (VP (VBP detests)
					 (NP-OB1 *T*-1))))))))

( (NP (D a)
      (N candidate)
      (CP-REL (CP-REL (WNP-1 (WPRO 0))				← one argument per CP-REL
		      (C that)
		      (IP-SUB (NP-SBJ (PRO he))
			      (VP (VBP admires)
				  (NP-OB1 *T*-1))))
	      (PUNC ,)
	      (CONJP (CONJ and)
		     (CP-REL (WNP-2 (WPRO 0))			← one argument per CP-REL
			     (C that)
			     (IP-SUB (NP-SBJ (PRO she))
				     (VP (VBP detests)
					 (NP-OB1 *T*-2))))))))

Gapping

Gapping involves instances of conjunction with an incomplete conjunct. In ordinary gapping, the gapped conjunct is a second conjunct, and the missing material includes the head of the phrase. In parenthetical gapping, which subsumes so-called right node raising, the incomplete conjunct interrupts a surrounding structure. In contrast to ordinary gapping, what is missing in the gapped constituent is not the head of the phrase, but other material. In both cases, omitting the gapped CONJP leaves a well-formed structure.

Ordinary gapping

Instances of ordinary gapping are marked by affixing -GAP to the relevant daughter of CONJP. Within the gapped constituent, grammatical functions are annotated as far as possible. 
( (IP-MAT (CONJ And)
	  (NP-SBJ (PRO I))
	  (VP (MD could)
	      (VP (VP (VB come)
		      (RP in))
		  (PUNC ,)
		  (CONJP (CONJ 0)
			 (VP (VP (VB work)
				 (NP-MSR (D a)
					 (N hour)
					 (QP (QR more)))
				 (PP (P of)
				     (NP (D a)
					 (N morning))))
			     (PUNC ,)
			     (CONJP (VP-GAP (NP-MSR (D a)
						    (N hour)
						    (QP (QR more)))
					    (PP (P of)
						(NP (D a)
						    (N evening)))))))))
	  (PUNC .)))

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (VP (VBD dug)
		  (PP (P around)
		      (NP (D the)
			  (NS hills))))
	      (CONJP (CONJ and)
		     (VP (VP (VBD made)
			     (NP-OB1 (D a)
				     (ADJP (ADJ little))
				     (ADJP (ADJ dry))
				     (N place))
			     (ADVP-LOC (ADV here)))
			 (PUNC ,)
			 (CONJP (CONJ and)
				(VP-GAP (NP-OB1 (D a)
						(ADJP (ADJ little))
						(ADJP (ADJ dry))
						(N place))
					(ADVP-LOC (ADV there)))))))
	  (PUNC .)))

( (IP-MAT (IP-MAT (NP-SBJ (D the)
			  (NPRS Republicans))
		  (VP (VBD went)
		      (PP (P with)
			  (NP (D the)
			      (NPR North)))))
	  (PUNC ,)
	  (CONJP (CONJ and)
		 (IP-MAT-GAP (NP-SBJ (NPRS Democrats))
			     (PUNC ,)
			     (NP (D the)
				 (NPR South))))
	  (PUNC .)))

Parenthetical gapping

With parenthetical gapping, the gapped constituent is marked by affixing -GAP to the gapped constituent's label, as with ordinary gapping. In addition, the gapped structure is enclosed in PAREN brackets. 
( (IP-MAT (CONJ for)
	  (NP-SBJ (PRO I))
	  (VP (GTD got)
	      (PAREN (CONJP (CONJ and)
			    (IP-MAT-GAP (NP-SBJ (PRO we))
					(VP (GTD got)))))
	      (NP-OB1 (Q+N nothing))
	      (PP (P from)
		  (NP (PRO them))))
	  (PUNC .)))

The gapped constituent is defined as the first (leftmost) non-CONJP descendant of PAREN. Most commonly, this is a daughter of CONJP, as above, but not necessarily. 

( (IP-MAT (NP-SBJ (PRO I))
	  (VP (DOD did)
	      (VP (GT get)
		  (PUNC ,)
		  (PAREN (CP-ADV-GAP (C though)
				     (IP-SUB (NP-SBJ (PRO I))
					     (VP (MD might)
						 (VP (ADVP (ADV easily))
						     (NEG not)
						     (VP (HV have)
							 (GTN gotten)))))))

		  (NP-OB1 (Q+N something))
		  (PP (P from)
		      (NP (PRO them)))))
	  (PUNC .)))
Right node raising is the subcase of parenthetical gapping where the material following PAREN is a single constituent. 
( (CP-ADV (C because)
	  (IP-SUB (NP-SBJ (PRO I))
		  (VP (HVP have)
		      (VP (VBN heard)
			  (PAREN (CONJP (CONJ and)
					(VP-GAP (HVP have)
						(VP (VBN seen)))))
			  (IP-ECM (NP-SBJ (ADJP (ADJ small))
					  (NS children))
				  (VP (VAG talking)
				      (PP (P about)
					  (NP (NS drugs))))))))))

( (FRAG (VP (VB Slice)
	    (RP up)
	    (PAREN (CONJP (CONJ and)
			  (VP-GAP (VB dry))))
	    (NP-OB1 (D the)
		    (NS apples)))
	(PUNC .)))

( (IP-MAT (CONJ for)
	  (NP-SBJ (PRO I))
	  (VP (DOD did@)
	      (NEG @n't)
	      (PAREN (CONJP (CONJ and)
			    (IP-MAT-GAP (NP-SBJ (PRO we))
					(VP (DOD did@)
					    (NEG @n't)))))
	      (VP (GT get)
		  (NP-OB1 (Q+N nothing))
		  (PP (P from)
		      (NP (PRO them)))))
	  (PUNC .)))

The following examples provide further illustrations of parenthetical gapping. 

( (IP-MAT (NP-SBJ (PRO I))
          (VP (MD can)
	      (VP (ADVP (ADV barely))
		  (VB understand)
		  (PUNC ,)
		  (PAREN (CONJP (CONJ but)
				(VP-GAP (MD will)
					(VP (ADVP (ADV nevertheless))
					    (VB read)))))
		  (NP-OB1 (D the)
			  (N book))))
	  (PUNC .)))

( (IP-MAT (NP-SBJ (PRO I))
          (VP (HVP have)
	      (VP (PP (P in)
		      (NP (D the)
			  (N past)))
		  (VBN understood)
		  (PUNC ,)
		  (PAREN (CONJP (CONJ but)
				(VP-GAP (DOP do)
					(NEG not)
					(VP (NP-MSR (ADJP (QP (Q any))
							  (ADJR longer)))
					    (VB understand)))))
		  (NP-OB1 (ADJP (ADJR such))
			  (NS books))))
	  (PUNC .)))

( (IP-MAT (NP-SBJ (PRO I))
          (VP (MD might)
	      (PUNC ,)
	      (PAREN (CONJP (CONJ but)
			    (IP-MAT-GAP (ADVP (ADVP (ADV then))
					      (ADV again))
					(PUNC ,)
					(NP-SBJ (PRO I))
					(VP (MD might)
					    (NEG not)))))
	      (PUNC ,)
	      (VP (BE be)
		  (ADJP-PRD (ADJ able)
			    (IP-INF (TO to)
				    (VP (VB understand)
					(NP-OB1 (D the)
						(N book)))))))
	  (PUNC .)))

( (IP-MAT (NP-SBJ (PRO I))
          (VP (HVP have)
	      (VP (PP (P in)
		      (NP (D the)
			  (N past)))
		  (PAREN (CONJP (CONJ but)
				(VP-GAP (DOP do)
					(NEG not)
					(VP (ADVP-TMP (ADV now))
					    (VB understand)))))
		  (VBN understood)
		  (NP-OB1 (ADJP (ADJR such))
			  (NS books))))
	  (PUNC .)))

Elision

Fully elided VPs are generally omitted, except when to do so would yield unnecessarily opaque structures (for instance, when elision targets the VP predicate of a small clause or the the first conjunct in a conjoined VP structure). 


( (CP-QUE-MAT (IP-SUB (MD Will)
		      (NP-SBJ (PRO you))
		      (VP go))
	      (PUNC ?)))

( (IP-MAT (INTJ Yes)
	  (PUNC ,)
	  (NP-SBJ (PRO I))
	  (VP (BEP am))
	  (PUNC .)))




( (IP-IMP (VP (VBI Let@)
	      (IP-ECM (NP-SBJ (PRO @'s))
		      (VP (VB go))))
	  (PUNC .)))

( (IP-IMP (INTJ Yes)
	  (PUNC ,)
	  (VP (VBI Let@)
	      (IP-ECM (NP-SBJ (PRO @'s))
		      (VP 0)))
	  (PUNC .)))




( (CP-QUE-MAT (IP-SUB (BED Were)
		      (NP-SBJ (PRO you))
		      (VP (VAG working)
			  (PP (P at)
			      (NP (D the)
				  (N time)))))
	      (PUNC ?)))

( (IP-MAT (INTJ Yes)
	  (PUNC ,)
	  (NP-SBJ (PRO I))
	  (BED was)
	  (VP (VP 0)
	      (PUNC ,)
	      (CONJP (CONJ and)
		     (VP (VAG going)
			 (PP (P to)
			     (NP (N school)))
			 (PP (P at)
			     (NP (N night)))
			 (PUNC ,)
			 (ADVP (ADV too)))))
	  (PUNC .)))

In connection with wh- constructions, elision can result in an antecedent without a corresponding trace; in this case, the antecedent receives the dummy index "x". For examples, see the section on elision in Degree and comparative constructions.

Partially elided VPs are annotated in the ordinary way as far as possible. Any constituents missing from the surface string are omitted, and the VP is given the dash tag -GAP. 

( (IP-MAT (NP-SBJ (PRO They))
	  (VP (VBP handle)
	      (NP-OB1 (D the)
		      (N problem))
	      (ADVP-TMP (ADV now))
	      (CP-ADV (WADVP-1 (WADV 0))
		      (C as)
		      (IP-SUB (NP-SBJ (PRO we))
			      (VP (DOD did)
				  (VP-GAP (ADVP *T*-1)
					  (ADVP-TMP (ADV then)))))))
	  (PUNC .)))