Adjunct Clauses

Adjunct clauses include subordinate clauses (i.e. those with overt subordinating conjunctions), purpose clauses and participial adjuncts. Subordinating conjunctions each select four trees, allowing them to appear in four different positions relative to the matrix clause. The positions are (1) before the matrix clause, (2) after the matrix clause, (3) before the VP, surrounded by two punctuation marks, and (4) after the matrix clause, separated by a punctuation mark. Each of these trees is shown in Figure 15.1.

  

Figure 15.1: Auxiliary Trees for Subordinating Conjunctions

(1) $\beta$Pss	(2) $\beta$vxPNs	(3) $\beta$puPPspuvx	(4) $\beta$spuPs

Sentence-initial adjuncts adjoin at the root S of the matrix clause, while sentence-final adjuncts adjoin at a VP node. In this, the XTAG analysis follows the findings on the attachment sites of adjunct clauses for conditional clauses ([#!iatridou91!#]) and for infinitival clauses ([#!Browning87!#]). One compelling argument is based on Binding Condition C effects. As can be seen from examples ((231))-((233)) below, no Binding Condition violation occurs when the adjunct is sentence initial, but the subject of the matrix clause clearly governs the adjunct clause when it is in sentence final position and co-indexation of the pronoun with the subject of the adjunct clause is impossible.

(230)0(230

(231)

Unless she_i hurries, Mary_i will be late for the meeting.  (231)0(231

(232)

$\ast$She_i will be late for the meeting unless Mary_i hurries.  (232)0(232

(233)

Mary_i will be late for the meeting unless she_i hurries. 

We had previously treated subordinating conjunctions as a subclass of conjunction, but are now assigning them the POS preposition, as there is such clear overlap between words that function as prepositions (taking NP complements) and subordinating conjunctions (taking clausal complements). While there are some prepositions which only take NP complements and some which only take clausal complements, many take both as shown in examples ((234))-((237)), and it seems to be artificial to assign them two different parts-of-speech.

(233)0(233

(234)

Helen left before the party.  (234)0(234

(235)

Helen left before the party began.  (235)0(235

(236)

Since the election, Bill has been elated.  (236)0(236

(237)

Since winning the election, Bill has been elated. 

Each subordinating conjunction selects the values of the <mode> and <comp> features of the subordinated S. The <mode> value constrains the types of clauses the subordinating conjunction may appear with and the <comp> value constrains the complementizers which may adjoin to that clause. For instance, indicative subordinate clauses may appear with the complementizer that as in ((238)), while participial clauses may not have any complementizers ((239)).

(237)0(237

(238)

Midge left that car so that Sam could drive to work.  (238)0(238

(239)

*Since that seeing the new VW, Midge could think of nothing else.