「评析」
1.对于虚拟条件句中时态的运用，首先应该熟记主从句动词与不同事实相反时的时态运用规则。解题时根据句子所表达的时间概念确定与什么事实相反，然后采用相应的时态。
① 如果与过去事实相反，从句中用过去完成时，主句中用would/should/could/might + have done的形式，如1)、3)、6)和7)。
1)If a better material______,the strength of the part would have been increased.(1992.6)
A.had been used
B.had been using
C.being used
D.using
答案：A
3)______ you were busy, I wouldn't have bothered you with my question.(1996.6)
A.If I realized
B.Had I realized
C.Did I realize that
D.As I realized
答案：B
注意：虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略，再把were, should或had 移到从句句首，实行倒装。
6)Had the weather been good,the children ______ out for a work.(2001.6)
A.had gone
B.could have gone
C.would go
D.went
答案：B
7)______ the advice of his friends, he would not have suffered such a heavy loss in his business.(2004.4)
A.If he took
B.If he should take
C.Were he to take
D.Had he taken
答案：D
② 如果与现在事实相反，从句中用一般过去时，主句中用would/could/might/should + 原形动词，如5)，表示与正在进行的事实相反用would/might/could/should + be doing的结构。
5)Do you think there would be less conflict in the world if all people ______the same language?
A.spoke
B.speak
C.had spoken
D.will speak
答案：A
③ 如果表示将来不可能实现的事情，从句中用过去时，或were to / should + 原形动词，以上题4)表示的就属于这种情况。
4)______,I should ask them some questions.(1997.6)
A.Should they come to us
B.If they come to us
C.Were they come to us
D.Had they come to us
答案：A
2.虚拟条件句有单一条件句，也有混合虚拟条件句，所以不能只根据从句与某一事实相反来判断主句就与该事实相反，同样，也不能想当然地认为主句与某一事实相反，从句也就与该事实相反。如2)：
2)If you ______that movie last night, you wouldn't be so sleepy.(1993.6)
A.hadn't watched
B.haven't watched
C.wouldn't have watched
D.didn't watch
答案：A
从句与过去事实相反，而主句与现在事实相反。
再如：
If he weren't such a kind man, he wouldn't have lent a hand to such people as you the other day.(从句与现在事实相反，主句与过去事实相反。)
Were my friends not to come tomorrow, I wouldn't have bought so many foods.(从句与将来事实相反，主句与过去事实相反。)
3.if引导条件状语从句时，可以将were/had/should提至句首，省略if.考试时经常是将省略if的与含有if的选项并列，在这种情况下，应注意分清从句的时态，尽管多数情况下都是倒装的结构为正确选项。如3)、4)、6)和7)。
再如：
Were they here now, they could help us.
=If they were here now, they could help us.
Had you come earlier, you would have met him
=If you had come earlier, you would have met him.
More Exercises
1)If I hadn't stood under the ladder to catch you when you fell, you ____ now.
A.wouldn't be smiling
B.couldn't have smiled
C.won't smile
D.didn't smile
答案：A
2)____ for my illness I would have lent him a helping hand.
A.Not being
B.Had it not been
C.Without being
D.Not having been
责任编辑：mman
