3 . 表示时间，意思是“无论何时，当……”，相当于 whenever。例如：

If I do not understand what he says , I always ask him .

　　If winter comes , can spring be far behind?

　　4 . 表示原因，意思是“既然”。例如：

　　If you don't like the job , why don't you change it?

四、as long as , so long as

　　1 . 表示时间，意思是“达……之久”。例如：

You can keep the book as long as you like .

　　During the holidays , I like to stay in the countryside as long as I can .

　　2 . 表示条件，意思是“只要”。例如：

　　As long as you tell truth , I'll try to help you .

　　You may take this book away so long as you return it on time .

　　3 . 表示原因，意思是“既然，由于，因为”。例如：

　　So long as the weather is changeable these days , we'd better get in wheat in time .　

　　So long as you are going to town tomorrow , you can do something for me .

五、since

　　1 . 表示时间，意思是“自从……以来”。例如：

　　I haven't heard from him since he left .

　　It is ten years since he joined the army .

　　2 . 表示原因，意思是“既然”。例如：

Since this method doesn't work , let's try another .

六、so... that与such... that的不同用法。

eg. He is such a clever boy/so clever a boy that he can solve these problems very fast.

There are so many people here that we don’t have enough seats for them.

七、so that

　　1 . 表示目的，意思是“以便，为了”。例如：

　　They started off early so that they could get there in time .

　　The student worked hard so that he might learn more .

　　2 . 表示结果，意思是“因此，结果是”。例如：

　　I went to the lecture early so that I got a good seat .

He spoke clearly , so that everyone heard .

【经典例题点评】

[例1] （2003春招）---- Was his father very strict with him when he was at school?

         ---- Yes. He had never praised him ____ he became one of the top student in his grade.          

         A. after  B. unless C. until    D. when

命题意图 考查复合句中状语从句与主句的逻辑关系。

解题思路 根据句意“父亲对他很严格，直到他成为年级里最好的学生是才表扬他”，选项中的四个连词只      有until符合题意，引导的是个时间状语从句。unless相当于if not“除非；如果不”，引导条件状语从句

正确答案 C

技巧点拨 要熟练掌握连词的基本含义和用法。

举一反三

1. （2004四川）______ you call me to say you' re not coming, I'll see you at the theatre.

A. Though      B. Whether   C. Until       D. Unless

2. I would appreciate it ______ you call back this afternoon for the doctor’s appointment.

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

3. The company has a free long-distance telephone number ______ customers may call with any question they have about in its products.

  A. so that  B. although  C. as      D. even if

[例2] （2004上海）Although he has lived with us for years, he ________ us much impression.

     A. hadn't left               B. didn't leave    C. doesn't leave             D. hasn't left

命题意图 考查主从句中的时态。

解题思路 上文中的完成时，对下文是暗示：尽管和我们已经一块住了多年，但是他还是没给我们留下什么印象。

正确答案 D

技巧点拨 主从句的时态要前后呼应。

举一反三

4. ---- Put these glasses away be