1. I must say he reads very well, and I shouldn’t be surprised if he ______ acting for a living one day.
A. had taken up B. takes up C. have taken up D. would have taken up
解析：(B)所给的四个选项中没有一个表示对未来的情况的虚拟的形式should+动词原形，或是were to do，因此可以断定if引导的条件句在这里最真实的条件句，用一般现在时表示一般将来时，故(B)是正确答案。
2. If I had seen the movie, I ______ you all about it now.
A. would tell B. will tell C. have told D. would have told
3. I’d rather you ______ anything about it for the time being.
A. do B. didn’t do C. don’t D. didn’t
4. Mary ______ my letter; otherwise she would have replied before now.
A. has received B. ought to have received
C. couldn’t have received D. shouldn’t have received
5. We didn't know his telephone number, otherwise we _____ him. ( 1995年6月四级第46题)
A) would have telephoned B) must have telephoned
C) would telephone D) had telephoned
解析：本题是与过去时相反的虚拟句，从句中用过去完成式，主句中用would have done。本句相当于if we had known his telephone number，we would have telephoned him。答案是(A) would have telephoned。
6. Jean doesn't want to work right away because she thinks that if she ______ a job she probably wouldn't be able to see her friends very often.(1996年1月四级第44题)
A. has to get B. had got C. were to get D. could have got
解析：本句的意思是：“琼不想马上就工作，她认为要是找了工作，就不能经常探访她的朋友了”。这说明，琼目前没有工作。句中假设的情况在近期内并不会存在。该条件句应当用表示将来情况的虚拟语气。条件从句的谓语用should或were to引出。因此C. were to get 是本题答案。选项A. has to get是陈述语气的现在时，不能用于虚拟条件句中。选项B. had got是虚拟语气的过去时，不能表示将来时间。选项D. could have got不能用于虚拟语气的条件从句中。
7. Look at the terrible situation I am in! if only I ____ your advice.(1993年6月四级第70题)
A. follow B. had followed C. would follow D. have followed
解析：if only 引出感叹句，意思是“要是……多好”，表示说话人的一种愿望，希望发生(事实上不可能发生)与过去事实相反的情况。本句的全句意思是：“看我现在的处境多糟糕!要是我听从你的劝告多好”。事实上，句中的“我”没有听从劝告，所以处境很糟糕。题中空格处应当用虚拟语气，答案是B。
8 .That tree looked as if it _____ for a long time.
a.hasn't watered b.had not been watered
c.didn't water d.wasn't watered
解析：本题测试as if 从句的虚拟语气。一般来说，as if 从句所表达的内容完全与实际情况相反或纯粹是一种假设时，通常使用虚拟语气。
9. I'd rather you ____ anything about it for the time being.
a. don't do b.did
c.didn't do d.would do
解析：would rather 表示愿望，后接从句用虚拟语气，用过去时。
10. Look at the terrible situation I am in! If only I ____ your advice
a.follow b.would follow
c.had followed d.have followed
解析：本题测试if only 引起的感叹句的虚拟语气。if only 引起的感叹句，相当于“how I wish +宾语从句”。其谓语动词形式与wish后的宾语从句形式相同。