15. --- Do you still remember when we went to Nanjing ?　　　

--- I can’t remember now but _________ sometime last summer?

A. might it be　　　　　　　　　　 　　　　 B. could it be　

C. could it have been　　　　　　　 　　　　 D. should it have been　

14. The new building will be built _________ was a wasteland 30 years ago.

A. in which　　 　　 B. where　　　　　 　 C. in what　 　　　 D. there

13. --- Look! Everything here is under construction.

　--- Oh, has the building once _________ for exhibition been pulled down, too?

A. being built 　　　 B. been built　　　 　　 C. to be built　 　 　 D. built

12. Never did we have to play “stand up”, “sit down”, “speak out”. I don’t _________ one student who didn’t try his best.

A. hear from　 　　 B. feel like　　　　 　　 C. think about　 　 D. know of