Only when _______ to explain _______ the reason for this.

A. did he start; she realized　　　　　　　　　

B. he started; did she realize

C. did he start; she had realized　　　　　　

D. he started; had she realized

I don’t think he could have done such a stupid thing last night, _____?

A. did he             B. could he　　 C. do I               D. hasn’t he

My grandfather would always read me a story when he came to visit us and I ___ enjoy it.

A. did use toB. used to　 C. would use to D. was used to

----Where ____ the dictionary? I can't see it anywhere.

----I ____ it right here. But now it's missing.

A. did you put; have put　 B. have you put; put C. had you put; was putting D. were you putting; have put

——where______the book?I can’t see it anywhere.
——I______it right here but now it’s gone.
A.did you put;have put 　 B.have you put;put
C.had you put;was putting D.were you putting;have put