状语从句2 条件状语从句

状语从句---条件状语从句

（1）if 和unless 引导的条件状语从句。if 表示正面的条件，意为“如果”；unless(=if---not )表示反面的条件，意为“除非，如果不”。Eg. ①If you had come a few minutes earlier, you would have met him.

②I may not come to see you recently unless I can complete the project ahead of time.

(2)in case, on condition that, providing(that), provided(that), supposing (that), suppose(that )等词汇意思相近，意为“万一，假设，假如，在---条件下”。

①In case there is a fire, what will we do first?

②Supposing/suppose(that)they refuse us, who else can we turn to for help?

They agreed to lend us the car on condition that we returned it before the weekend.

典例 The company promised to give us a discount we pay in advance.

A.even if

B.as if

C. so that

D. provided that

(3)as long as (=so long as )引导语气强烈的条件状语从句，意为“只要”。

Eg. I don't mind where you go, as long as you're back before midnight. (4)在“祈使句+and/or/or else/otherwise+陈述句”句型中，祈使句在意义上相当于条件状语从句。

Eg.①Run faster and you will catch the bus. =

Work hard, otherwise you will fail.

(5)if only”如果---就好了”和only if “只有”也可引导条件状语从句。但是only if 置于句首时，主句用部分倒装。

Eg. If only I had a dog, I wouldn't be so lonely.

Only if a teacher has given permission is a student allowed to leave the room.

复习时要掌握条件状语从句的四大考点：

（1）考查引导词。只要弄清楚上下文的语义关系，并掌握引导词的意思，就能准确快速地写出答案。

（2）考查时态。在含有条件状语从句的复合句中，主句若用一般将来时，从句往往用一般现在时表示将来。

（3）考查条件句中的虚拟语气。条件句中的虚拟语气主要体现在if 型虚拟条件句和错综时间的条件句中。

①if 可引导真实的条件句，表示假设的情况有可能实现。

Eg. I will go out if it doesn't rain.

② if 引导虚拟条件句，表示假设的情况很难实现或与事实相反。（1）与现在事实相反，从句谓语动词用过去时（did/were）, 主句谓语动词用would/should/could/might+do

（2）与过去事实相反，从句谓语动词用过去完成时（had done）,主句谓语动词用would/should/could/might + have done

（3）与将来事实相反，从句谓语动词用should do/did/were to do ,

主句谓语动词用would /should/could/might+do

Eg.① If I (be) ten years younger, I would start all over again.

②If you (warn)him of the danger, he would not have been seriously injured.

典例（2014.北京）We back in the hotel now if you didn't lose the map.

A.are

B. were

C. will be

D. would be

(2013.福建) --- Do you think George has passed the driving test ?

---- No. If so, he his car to our college yesterday.

A.would drive

B. drove

C. would have driven

D. had driven

注意：在if 虚拟条件句中，如果要省略if, 必须把从句中的had, were,或should 置于句首，构成部分倒装。

Eg. 【①】Were I you, I would find a chance to make up with him. 【②】Had you had a deep communication with your mother, she would have supported you .

【③】Should I have time, I would go and watch the football game.

③If 引导错综时间的条件句

在错综条件句中，条件从句和主句的谓语动词发生的时间背景不同，因此，条件从句和主句的谓语要根据谓语动作各自的时间背景选用不同的形式。

Eg. If I were you, I wouldn't have missed the film last night.