Wh-moved object of a P

Wh-questions can be formed on the NP object of a complement PP as in sentence ((202)).

(201)0(201

(202)

[Which dog]_i did Beth Ann give a bone to ? 

The by phrases of passives behave like complements and can undergo the same type of extraction, as in ((203)).

(202)0(202

(203)

[Which dog]_i was the frisbee caught by ? 

Tree structures for this type of sentence are very similar to those for the wh-extraction of NP complements discussed in section 14.3 and have the identical important features related to tree structure and trace and inversion features. The tree in Figure 14.4 is an example of this type of tree. Topicalization of NP objects of prepositions is handled the same way as topicalization of complement NP's.

{Ditransitive with PP tree with the object of the PP extracted: $\alpha$W2nx0Vnx1pnx2