2013年12月大学英语六级考试虚拟语气讲解19
2013年12月大学英语六级考试虚拟语气讲解19
虚拟语气用在lest，for fear that及in case引导的目的状语从句中
在由lest等引导的目的状语从句中需用虚拟语气，表示“以防，以免”等意思，其谓语动词多由should ＋动词原形构成，should也可省略。
例如：
⑴、He was punished lest he should make the same mistake again．他被处以惩罚以免他再犯。
⑵、The mad man was put in the soft-padded cell lest he _____ himself.
a. injure b. injured c. had injure d. would injure
这个疯子被关进墙上装有衬垫的病房，以免伤了他自己。（答案是a）
介词短语表示虚拟
有时假设的情况并不以条件从句表示出来，而是通过一个介词短语来表示，或通过上下文或其他方式表示出来。如but for, but that…, in case of, otherwise, supposing, under more favourable condition, without 等表示让步假设。
1).He worked very hard; otherwise he might have failed. (他刻苦工作，不然他就失败了。)
2).We could have done better under more favorable conditions.(假设我们有更有利条件，我们还会做得更好。)
3). But for his help，I .
［A］should not have succeeded
［B］had not succeeded
［C］did not succeed
［D］have not succeeded
4). But that he came to help me, I .
［A］could not have succeeded
［B］did not succeed
［C］could not succeed
［D］can’t but succeed
