II.虚拟语气
(一)一般虚拟结构
类别 | 用法 | 例句 | |
If引导的条件从句 | 与现在事实相反 | 从句动词：过去式（be用were） 主句动词：should/would/could/might+动词原形 | If he were here, he would help us. |
与过去事实相反 | 从句动词：had+过去分词 主句动词：should/would/could/might+have+过去分词 | If I had been free, I would have visited you. | |
与将来事实相反 | 从句动词：过去式 / should+动词原形 / were+不定式 主句动词：should/would/could/might+动词原形 | If it should rain tomorrow, we would not go camping. | |
注意:主句中的should只用于I、we，但在美国英语中，should常被would代替;从句中的should可用于各种人称，且不可以被would所代替。
(二)混合虚拟结构
1.不同时间的虚拟
If he had listened to me, he would not be in trouble now.(从句与过去事实相反，主句与现在事实相反)
If he had told me yesterday, I should know what to do now. (从句与过去事实相反，主句与现在事实相反)
If I were you, I would have gone to her birthday party. (从句与现在事实相反，主句与过去事实相反)
If you hadn’t lent me some money, I couldn’t have bought the new house and most likely I would be still living in the dangerous house now. (从句与过去事实相反，and后面的主句与现在事实相反)
2.虚拟与陈述的混合
He could have passed the exam, but he wasn’t careful enough.
You should have come earlier. The bus left a moment ago.
(三)特殊句式虚拟结构
1.省略连词if。在书面语中，如果虚拟条件从句中有were，had 或 should，可以把if省略，把这几个词放到主语之前，构成主谓倒装。
Should he come (If he should come), tell him to ring me up. 他要是来了，让他给我打个电话。
Were I you (If I were you), I would not do it. 我要是你，就不做这事。
2.suggest, order, propose, request, require, demand, advise, insist+ 宾语从句(should )do
He suggested that we (should) save money for the future.
The undergraduate insisted that he (should) go to work in the south.
注意：当suggest表示暗示，insist表示坚持观点,事实时，后接的宾语从句应当用真实语气。
His silence suggested that he agreed with my decision.
He insists that doing morning exercises does good to people’s health.
3.It is suggested/advised/ordered/requested/required…+ that从句(should) do
It is proposed that more students should go to university.
4.My advice/suggestion/request/requirement/order/proposal…+ is +表语从句(should)do
My advice is that you should practise speaking English as often as possible.
The order from the commander was that the troops should set off for the front immediately.
5.His suggestion/advice/request/requirement…+ 同位语从句(should )do+ is..
The request that they should get more is reasonable.
6.It is natural/necessary/strange +that从句 (should) do表惊奇、怀疑、惋惜、不满、理应如此等。
It’s strange that he should have missed the train. (表竟然)
It is important that we should learn from others.(表理应如此)
It is a pity that he should not go with us.(表惊讶、不满)
7.wish + that clause (did/were 与现在相反)
wish + that clause (would/could/might + do与将来相反)
wish + that clause ( had done 与过去相反)
I wish I could go with them tomorrow.
I wish I had never met him.
8.It is (high/about) time + 从句(did或should do )
It is (high/about) time we went home.
9.would rather + clause (did 与现在或将来相反);(had done 与过去相反)
I would rather you came tomorrow.
I would rather you hadn’t told her the news.
10.省去条件从句或主句：表示虚拟语气的主句或从句有时可以省略，但其含义仍可以推知。
①省去条件从句
You could have washed your clothes yourself. 你本可以自已洗衣服的。
省去了"If you had wanted to")(事实是:你自己没洗衣服，因为你不想洗。)
②省去主句(常用以表示愿望) If only + clause ( did/were与现在相反)/ (would/could/might + do与将来相反) /( had done 与过去相反) “要是…….就好了“
If my grandmother were with me! 如果我的祖母与我在一起多好啊!(事实是:祖母已不在世。)
If only she had not left! 如果她没走就好了!(事实是:她已经走了。)
If only he would come tomorrow!
If only I had taken her advice!
If only I were ten years younger!
注意：only if是“只要”的意思，从句中用陈述语气。
