三、语法解读

　　条件状语从句和让步状语从句

　　1.条件状语从句的引导词

　　由if(如果),unless(除非)，as long as(只要),on condition that,in case,once等引导。例如:

　　You can not learn a language well unless you work hard.

　　除非你努力学习,否则学不好语言。

　　I will come on condition that Mary is invited too.

　　如果也邀请玛丽,我就会来。

　　If you wake up before me,give me a call.

　　如果你醒的比我早,请叫我一声。

　　I will give you the money as long as you go with your elder brother.

　　只要你同你哥哥一块去,我就会给你钱.

　　Once you give it to him,you will never get it back.

　　一旦他把东西得到手，你就再也要不回来了。

　　2.真实条件句和非真实条件句

　　假设的情况有可能发生的条件句叫真实条件句，使用陈述语气；如果主句是将来时，从句就用一般现在时。假设的情况完全是一种假设或发生的可能性不大的条件句叫非真实条件句，在非真实条件句中，用虚拟语气。例如:

　　I will go out with you if it is fine tomorrow.

　　明天天气好的话，我就和你一块去。

　　If it were not raining now,I would not be staying at home.

　　如果现在不下雨的话,我就不会待在家里了。

　　If it should rain tomorrow,we would stay at home with him.

　　如果明天下雨的话，我们就跟他待在家里。

　　If you had stayed with us,you would have seen him.

　　如果那时你跟我们在一块的话，你就会见到他了。

　　3.让步状语从句的引导词

　　让步状语从句由though,although,as(尽管),even if,even though,whoever,whatever,whichever,whenever,wherever,however,no matter+疑问词引导。例如:

　　Though we were very tired,we felt very happy.

　　尽管我们很累，却感到很开心。

　　I will get there,even if I have to walk.

　　我就是走也要走到那儿去。

　　She is lovely,even though she is annoying sometimes.

　　尽管有时她挺烦人，但她还是挺可爱的。

　　We will make a trip even if the weather is bad.

　　尽管天气不好，我们还是要去旅行。

　　I'll post that letter whatever Wilson says.

　　I'll post that letter no matter what Wilson says.

　　不管威尔逊讲什么，我都要寄出那封信。

　　Whenever you come back,do not wake me up.

　　No matter when you come back,do not wake me up.

　　不管你什么时候回来，都不要吵醒我。

He carries a book in his pocket wherever/no matter where he goes.