4．They arrived at a house，in__front__of__which sat a little boy.他们来到一座房子，房前坐着一个小男孩。

5．The reason for__which I bought the roses is that Mary likes them.

我买玫瑰的原因是玛丽喜欢。

Ⅲ.句型转换

1．There used to be a time when the Chinese people struggled for freedom.

→There used to be a time during/in which the Chinese people struggled for freedom.

2．Don't you want to explain the reason why you were late for the important meeting?

→Don't you want to explain the reason for which you were late for the important meeting?

3．He lives in an old room，whose roof has been damaged in the storm.

→He lives in an old room，the roof of which has been damaged in the storm.

4．We then moved to Paris where we lived for six years.

→We then moved to Paris in which we lived for six years.