BW connects "what" (as a direct or indirect question word) to 
various verbs like "think", "decide", which are not really
transitive verbs but which can connect to "what" in object-
type questions.

	  +----BW-----+
          |  +----I---+
          |  +SI-+    |
	  |  |   |    |
	What do you think?

	*I thought a good idea today.

BW is also used with verbs like "tell" and "ask", which can
connect to "what" as if it were an indirect object: "What did
you tell him?"

"Whatever" can be used in this way as well: "Whatever you think
is fine".