第一节 语法和词汇知识(共15小题；每小题1分，满分15分)
21．—I probably shouldn’t have any more cake.
—Oh，________.It won’t kill you.
A．go ahead B．hold on，please C．you’re welcome D．that’ll do
22. ______ is required in the library regulations that any book borrowed be returned by due time.
A. As B. What C. It D. Which
23. ______ to the sun for too long in that area may probably cause skin cancer.
A. Exposed B. Being exposed C. Exposing D. To be exposed
24．Bob could have seen the famous pop star ______ yesterday morning．
A．did he come B．if he came C．had he come D．if he should come
25. We _____you were in trouble at that time, otherwise we could have given you a hand.
A. didn’t know B. haven’t know C. don’t know D. hadn’t know
