Where can the gap be?  See grammatical-functions-semantic-roles
      list:  
      --------------------
	     Main clause:
	     Check for gaps in each grammatical function.  

	     Most of the semantic roles are going to be adpositional
	     phrases or case marked NPs, so spot check a few of them.

      (Note for analysis of data: For each item,
      what happens to the questioned element: no change (in
      situ); moved to initial position; moved to final position;
      clefted; forms intonation nucleus; other.  Again this is about
      describing the data once you have it.)

      -------------------
	Subordinate clause, non-finite, and nominalized clauses.
	See subordinate-nominalization list.
	
	Check for gaps in each grammatical function again, and spot
	check the semantic roles.

      -------------------
         The element next to a subordinating conjunction:
	 *Who do you think that ___ left.
	 (Did they just add this because of the Empty Category
         Principle?) 

      -------------------

         Questioning a sub-component of NP:
         Two factors:  (1) what is the function of the NP  (2) what
         part of the NP is extracted.

 
         e.g., The part of NP is the object of a preposition:  check
         (1) for the grammatical function of the head NP, (2) the
	 semantic role of the PP, especially whether it is an
	 arguement or adjunct of the head N.
	
	 NP is direct object:
	    Who did you see pictures of ----?  (PP is argument of head N)
	    What did you read a book about ----? (PP is argument of head N)
	    *What did you buy [np a watch with ----?] (PP is adjunct of N)
	 NP is oblique:
	    Who did you look at pictures of ---?
         NP is second accusative or accusative of a dative-accusative:
	    Who did you show him the pictures of ----?
	    Who did you show the pictures of ---- to him?
	 NP is subject:
	  *Who did pictures of --- bother you?
         ETC. FOR THE REST OF THE GRAMMATICAL FUNCTION LIST.

	 e.g., The part of NP is a PP:
	 NP is diret object:
	    Of whom did you see pictures ---?
	    *With what did you buy [a watch ---?]
         ETC. FOR THE REST OF THE GRAMMATICAL FUNCTION LIST.

	 e.g., The part of NP is possessor:
	 Whose book did you see?
	 *whose did you see book?

	 The part of NP is a number or degree
	 The rest of the NP pied pipes along.

	 How many times have you seen the movie.
	 How large an area would it cover.	 

	 ---------------------
	 Questioning a sub-component of PP:
         (notes for analysis of data: is preposition stranding
	 allowed?) 
	 
	 What did you buy [np it] [pp with ---]?
	 What day did you do it on ---?

         ---------------------
	 Questioning from coordinate structures:

	 A whole conjunct: (1) category of conjunct (2) grammatical
	 function and semantic role of the whole coordinate structure:  

        e.g., Category is NP
	Gramamtical function is object:
	 *Who did you see her and ---?
	Grammatical function is subject:
	 *Who did John and --- talk to Bill?

        Part of a conjunct:
	e.g., Who did you read books about --- and see pictures of
	flowers.

	Across the board:
	e.g, What did you see books about ---- and pictures of ---?

	 ---------------------------
	 Questioning multiple elements:

	 e.g., Who talked to who?  (except that some languages may allow
	 this as a regular question, not just an echo question)

	 (CS say to check all combinations of functions/roles of the
	 multiple questioned elements.  That must have kept the field
	 linguists busy for a while.)

	 ----------------------------
	 Pied piping

	 About what did you read?
	 *A book about what did you read?
          (English can do this in relative clauses:  
	  I like fishing, [a book about which] I have read over and
	  over.
          I read the book about sewage systems, [the height of the
	  lettering on the cover of which] the government prescribed.)


	  In main clauses:
	  Whose book did you see ---? 
	  *Whose did you see --- book?