实力测验――221页

一、

1．and

2．but

3．or

4．and

5．or

6．nor

7．When

8．if

9．because

10．but

11．if

12．since

13．or

14．or

二、

1．what

2．when

3．whether

4．why

5．which

6．how

7．that

8．who

9．how many

10．how long

三、

1．studies→study

2．are→is

3．are→am

4．love→loves

四、

简单句：

These questions were too difficult for us to answer．

复合句：

These questions were so difficult that we couldn't answer them．