语法和词汇知识
21. --You look tired today. Did you not sleep well last night?
--Well, I _____ till two in the morning the past three days.
A. worked B. have worked C. have been working D. had worked
22. I always worry about making a good _____ when I meet people for the first time.
A. approach B. impression C. reputation D. improvement
23. --Did you switch your jobs?
--Yeah, I did, _____ it’s definitely been a change for the better.
A. but B. and C. or D. so
