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# Distribution of Complementizers

Like other non-arguments, complementizers anchor an auxiliary tree (shown in Figure 8.1) and adjoin to elementary clausal trees. The auxiliary tree for complementizers is the only alternative to having a complementizer position built into' every sentential tree. The latter choice would mean having an empty complementizer substitute into every matrix sentence and a complementizerless embedded sentence to fill the substitution node. Our choice follows the XTAG principle that initial trees consist only of the arguments of the anchor8.6 - the S tree does not contain a slot for a complementizer, and the COMP tree has only one argument, an S with particular features determined by the complementizer. Complementizers select the type of clause to which they adjoin through constraints on the <mode> feature of the S foot node in the tree shown in Figure 8.1. These features also pass up to the root node, so that they are visible' to the tree where the embedded sentence adjoins/substitutes.

{Tree $\beta$COMPs, anchored by that

The grammar handles the following complementizers: that, whether, if, for, and no complementizer, and the clause types: indicative, infinitival, gerundive, past participial, subjunctive and small clause (nom/prep). The <comp> feature in a clausal tree reflects the value of the complementizer if one has adjoined to the clause. The <comp> and <wh> features receive their root node values from the particular complementizer which anchors the tree. The COMPs tree adjoins to an S node with the feature <comp>=nil; this feature indicates that the tree does not already have a complementizer adjoined to it.8.7 We ensure that there are no stacked complementizers by requiring the foot node of COMPs to have <comp>=nil.

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XTAG Project
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