非限定性定語從句例題

由as, which 引導的.非限定性定語從句，as和which可代整個主句，相當於and this或and that。As一般放在句首，which在句中。

As we know, smoking is harmful to ones health.

The sun heats the earth, which is very important to us.

典型例題

1)Alice received an invitation from her boss, ___came as a surprise.

A. it B. that C. which D. he

答案C. 此為非限定性從句，不能用 that修飾，而用which.，it 和he 都使後句成為句子，兩個獨立的句子不能單以逗號連線。況且選he句意不通。

2)The weather turned out to be very good, ___ was more than we could expect.

A. what B. which C. that D. it

答案B。which可代替句子，用於非限定性定語從句，而what不可。That 不能用於非限定性定語從句，it不為連詞，使由逗號連線的兩個句子並在一起在英語語法上行不通。

3)It rained hard yesterday, ____ prevented me from going to the park..

A. that B. which C. as D. it

答案B.