【语境展示】

观察下面两组句子，并试着归纳它们的不同点。

A

1. The man who / that called yesterday wanted to buy the house.

2. The person (that / who / whom) you should ask is Mr. Ball.

3. Please show me the book which / that is written by Mo Yan.

4. You know the little Italian restaurant (which / that) I mentioned in my letter?

5. Help is needed for families whose homes were destroyed in the earthquake.

6. The hotel where we stayed was both cheap and comfortable.

7. There are times when I wonder why I do this job.

8. The reason why I'm late is that I missed the bus.

9. The woman with whom you shook hands just now is head of our company.

10. The death of his son was an experience from which he never fully recovered.

B

1. Mrs. Smith, who has a lot of teaching experience, will be joining us in the spring.

2. Mary, who / whom we were talking about earlier, has just walked in.

3. The winner was a Brazilian player, whose name I have forgotten.

4. The dam, which is the biggest in the world, is 3,830 metres long.

5. You lent me some money, which I never repaid you.

6. One of the boys kept laughing, which really annoyed Jane.

7. In 1963 we moved to Boston, where my grandparents lived.

8. The Queen's last visit was in May, when she opened the new hospital.

9. I met Mr. Smith, with whom I used to work.

10. This house, for which Mr. Smith paid $150,000, is now worth $300,000.

【自我归纳】

通过观察我们可以发现：A组句子中的定语从句都是限制性定语从句，B组句子中的定语从句都是非限制性定语从句。限制性定语从句与非限制性定语从句主要有以下区别：

1. 形式不同

限制性定语从句与主句之间不能用逗号隔开（A组句子），非限制性定语从句与主句之间通常用逗号隔开（B组句子）。

2. 作用不同

限制性定语从句对先行词进行修饰和限制，如果去掉，主句的意思就会不完整、不明确或失去意义（A组句子），非限制性定语从句对先行词进行________，与主句的关系不十分密切，如果去掉，主句的意思仍然完整（B组句子）。

3. 关系词不同

限制性定语从句可以由who, whom, that, which, whose, where, when, why及“介词 + which / whom” 等来引导 （A组句子）；非限制性定语从句通常由who, whom, which, whose, when, where及“介词 + which / whom”等来引导（B组句子）。另外，在限制性定语从句中，关系代词在从句中作________ 时可以省略（A组句2、句4），而在非限制性定语从句中关系词一律不能省略（B组句子）。

4. 关系代词指代不同

限制性定语从句的关系代词一般指代一个名词或代词（A组句1至句5、句9、句10）；非限制性定语从句的关系代词则既可指代一个名词或代词（B组句1至句5、句9、句10），也可以指代整个主句（B组句6）。

【即学即练】

用适当的关系词补全下面短文。

Most people have never heard of Tim Berners-Lee. He is not as famous as Bill Gates, 1. ________ name has become very well known.

Berners-Lee, 2. ________ works in a small office at the Massachusetts Institute of Technology, is the creator of the World Wide Web. He was born in England in 1955. His parents, 3. ________ helped design the world's first commercially available computer, gave him a great love of maths and learning.

In 1980, Berners-Lee went to work at a physics laboratory in Switzerland, 4. ________ he had a lot of material to learn quickly. He had a poor memory for facts and wanted to find a way to help him keep track of the things 5. ________ he couldn't remember. He designed a software program 6. ________ allowed him to create a document (文件) that links (连接) to other documents. He continued to develop his idea through the 1980s.

In 1991, his project became known as the World Wide Web. The number of people 7. ________ used the Internet started to grow quickly. However, Berners-Lee is not completely happy with the way in 8. ________ the Web has developed. It has become a passive tool for so many people, not the tool for creativity 9. ________ he had imagined.

In 1999, he published a book called Weaving the Web, 10. ________ he answered questions he was often asked.