37.________________certain that his invention will lead to the development of production.

33.I don't think_____________difficult for a Chinese student to master a foreign language within five years
34.

27.—Did Li Lei call me while I was out?
28.　—Yes, it was ____________that called you.
29.

25.Has __________been decided when we are to hold the sports-meeting?
26.

22. —Has the boy got his bicycle now?
23. 　—Yes, the police gave 　　.
24.

19..Someone is at the door, who is_________?
20.

15.__________is very clear to everyone that he's round and tall like a tree.
16.

14.Many people now make_________a rule to buy cards for their friends before Christmas.

11 .He felt_____ to work for human rights and progress.

10 .--- Do you like _____here?
---Oh, yes, the air, the weather and the way of life. Everything is so nice.