要想真正学好英语语法,还是要了解整个语法体系,请参考:怎样学好英语语法? - Ernest 的回答
当然,对于需要应试的各位,大家只要知道虚拟语气用于状语从句和名词性从句,并了解它的常见搭配即可,即记住上面的从句主句搭配表格:
1)用于状语从句
与过去事实相反
从句:过去完成时had done
主句:would/ should/ could / might + have done
If I had gotten there earlier, I would/ should/
could have met her.
If he had taken my advice, he would not
have made such a mistake.
与现在事实相反
从句:过去时(be只用were)
主句:would/ should/ could/ might + do/ be doing
If I knew his telephone number, I would tell
you.
If there were no air or water, there would
be no living creatures on Earth.
与将来预期相反
从句:过去时(be只用were)或should / were to + 动词原形
主句:would/ should/ could / might + 动词原形
If there were a heavy snow next Sunday, we
would not go skating.
If she were to be there next Monday, I would
tell her about the matter.
If he should come here tomorrow, I should,
would talk to him.
「与将来预期相反」要多说两句:上面两种情况的「过去」「现在」都是对已知的事实进行反向虚拟,但是「将来」尚未发生,所谓虚拟是指对于将来正常情况的反向虚拟,也就是说这种虚拟的可能性极低,正常情况下是不会发生的,应该理解为「万一」「just in case」,是对前面某种assertion的一种补充,一种保险的说法。比如上面的第一个例句即「万一下周下雪(正常应该是不会下雪的)」,第二三例句即「TA要是来的话(我觉得TA不大可能会来)」。
2)用于名词性从句
表意见、命令、要求的动词/名词 + that + (should)
+ 动词原形。这种就更简单了,只要记住下面这些词即可。
常用动词
advise/ suggest/ insist/ request/ require/
order/ demand/ command/ decide/ recommend等
Jane’s uncle insisted that she (should) not
stay in the hotel.
The workers requested that their working conditions
(should) be improved.
It was suggested that Jane (should) have a
medical examination.
常用名词
suggestion/ proposal/ order/ advice/ demand/
requirement等
My suggestion is that you (should) send a few
soldiers to help them.
He makes the demand that she (should) leave
the place at once.