--- When did your father come back last night?
--- He didn’t come back _______ he finished all the work.
A. until B. while C. if D. unless
I think Kate will come if she _______ free this afternoon.
A. is B. will be C. was D. are
---I hope you _______ my party next weekend?
--- OK, I _______ .
A. to come in; will B. come to; will
C. came: am D. will come to; will
I was doing my homework _______ mother was cooking.
A. when B. while C. as D. what time
No one knows what _______ in fifty years.
A. will our life be like B. is our life like
C. our life will be like D. our life is like
If there are trees, the air in our city will be cleaner.
A. less; more B. more; more C. more; much D. much; more
