微课M6U3Grammarandusage.ppt

Unreal conditionals
虚拟语气中的非真实条件句
长郡梅溪湖中学 张梦林
Grammar and usage
虚拟语气可用于条件句和其它一些从句中。虚拟语气用于条件句中比较多，情况也比较复杂，所以要特别加以注意。首先要判断一下是否应该用虚拟语气，因为条件句分为两种，一种是真实条件句，一种是非真实条件句，只有在非真实条件句中才用虚拟语气，在真实条件句中，要用陈述语气。
虚拟语气的介绍
Observe the following sentences and tell
whether they are real or unreal
conditional clauses.
If we go on polluting the world, it won’t be fit for us to live in.
If you are busy doing your homework, I won’t interrupt you.
If you have finished cleaning the classroom, you can go home now.
(Under these conditions, the things are sure to happen.)
If there were a lot of good restaurants in the city, this would make it more attractive.
(There aren’t many good restaurant now.)
If a lot of people spoke English, it would be very helpful for tourists.
(Not many people can speak English now.)
非真实条件句的时态表达
如果假设的情况完全不存在或者实现的可能性很小,可以说几乎没有时,就需要用虚拟语气来表达,也就是说,这时的条件句是非真实的条件句。此时的句子时态比真实条件句中的时态后退一步。
虚拟语气
条件从句和主句中的虚拟语气
动词的过去式（be动词一般用were）
would  / should  / could  / might +动词原形
would  / should  / could  / might + have +过去分词
had +过去分词
would  / should  / could  / might +动词原形
①动词的过去式（be  动词一般用were）
②were to +动词原形
③should +动词原形
【即学即练】
根据括号内的提示补全下面句子或对话。
1. Ken got to the station in time to catch his
train. If he __________ (miss) it, he
_______________________________________
(be) late for his interview.
2. I think there are too many cars. If there
________ (not, be) so many cars, there
_______________________________________
(not, be) so much pollution.
would / could / might / should have been
had missed
weren’t
wouldn’t / couldn’t / mightn’t / shouldn’t be