5. We must get up early, _______ we have a long way to go.

A. so　 　　　 B. for　　　 　C. but　　　 　　D. or

引导原因状语从句的连词有：because, since(既然), as(由于)等。

在表示原因的这三个词中, because语气最强，用来说明人所不知的原因，常用来回答由why提出的问题; as或since用来说明不重要或已为人们所知的原因，since比较正式。另外，并列连词for也可以连接一个分句，对并列句的前一个分句所叙述的事件原因加以追述，两个分句之间用逗号隔开。如：

a. I didn’t go, because I was afraid.

b. As (Since) you are not feeling well, you’d better　stay at home.

例题：

4. I was late for class yesterday _______ there was Something wrong with my bike.

A. when　　　 　B. that　 　　C. until　　 　D. because

3. 他们都买了往返机票，为的是能节省点儿钱。

They all bought _____ air tickets, _____ _____ they could ____ some money.

2. When I got the news that the ship would sink, I was _______ frightened _______ my legs couldn’t move forward.

A. so, that　 　B. very, that　 　C. too, that　 D. too, to

1. She is _______ good doctor that everyone wants to see her.

A. such a　 　　　 　B. a such　　　 　C. a very　　　 　D. so

3. so that还可以引导目的状语从句，意为“以便；为的是”，此时可用to或in order to替换。试比较：

a. They missed the bus so that they were late for class. (结果状语从句)

b. They got up early so that they could catch the　first bus. (目的状语从句)

→They got up early to (in order to) catch the　first bus.

例题：

2. so...that在某种情况下可以和too...to或enough to结构相互转换。如：

句a可以转换成：He spoke too fast for me to follow.

句b可以转换成：He is careless enough to make mistakes at times.

引导结果状语从句的连词有so/such... that(如此……以至于), so that(以致，结果)等。

1. so... that常用于“so + adj./adv. + that”，“so + adj. + a/an + n. + that”或“so many/much/few/little (+adj.) + n + that”结构；such... that常用于“such + (a/an) + adj. + n. + that”结构。如：

a. He spoke so fast that I couldn’t follow him.

b. He is such a careless man that he makes mistakes at times.

2.在由since 引导的时间状语从句中，主句用现在完成时，从句用一般过去时。也可用“It is +一段时间+since+时态为一般过去时的从句”句型。

例题：-Do you know Betty very well?

-Yes, she and I _______ friends since we met in Guangzhou last summer.

A. have made　 　B. have become

C. have been　 　D. have turned

Key: B A A A B C

引导条件状语从句的连词有if(如果)；unless(除非)，它相当于“if ... not”；as(so) long as (只要)等。

例题：We’ll go to visit Tian’anmen Square _______ it doesn’t rain tomorrow.

A. if　　　　 B. as soon as　　　 C. when　　　　 D. since

主从句的时态呼应

1．　　　　　　　 当状语从句表示将来时，在when, after, before, until, as soon as等引导的时间状语从句和if引导的条件状语从句中，从句通常不用一般将来时，而用一般现在时。

例题：Don’t leave until he _______ back.　

A. have come　 　B. comes

C. will come　 　D. came