在虚拟语气中,除了记住一套与时态相对应的规范用法之外,以下几点也是不容忽视的:
l 、名词性从句中要用过去时或 should+ 动词原型构成虚拟语气。如: It is time we went home .
2 、 would rather , had rather 后的从句动词用相当于陈述语气的过去时来表示现在或将来发生的动作。如: I would rather you went with her .我 宁愿你 跟她走。只有当 would rather 后面动作的主体与前面主语一致时才可以用不带 to 的动词不定式,如: I ' d rather take the important letter with me .在这个句子中, rather 后面的主语为 I ,和前面的主语一致,所以用的不是过去式,而是不带 to 的动词不定式。
3 、在 it is important / suggested / necessary / proposed 等结构后的主语从句中要用虚拟语气表示应该做什么事情,即用动词原形或 should+ 动词原型,如: It is important that you(should)be here on time .再如:
It is of the utmost importance that you _______here on time .
A . be B . shall be
C . are to be D . must be
这个知识点是上文中的第三点,显然答案是 A ,其中的 should 被省略了。类似的可以引起主语从句为虚拟语气的形容词或过去分词还有 appropriate, advisable , better , imperative , insistent, natural , preferable, strange, urgent, vital, desirable , demanded , recommended, required 等。
4 、词组 but for 相当于 were it not for 或 had it not been for, 表示一种含否定意义的条件,后面一般加名词或名词短语,如: He might have been killed but for the arrival of the police .要不是警察来了他本可能被杀死。
5 、在某些表示祝愿的句子里需要用虚拟语气,如: May you be happy all your life!