张志胜 张爱军
　　
　　非限制性定语从句和主句的关系不十分密切，只对主句中的先行词作附加说明。如果去掉，主句仍然表达明确、完整的概念。它和主句之间往往用逗号分开。
　　
　　引导非限制性定语从句的词有：关系代词who, whom, which；关系副词where, when；形容词whose等。
　　
　　使用非限制性定语从句时应注意以下几个问题：
　　
　　1. 什么情况下用非限制性定语从句。
　　
　　（1）先行词为人名或地名等时。如：
　　
　　The famous basketball star, Joden. ________ tried to make a comeback, attracked a lot of attention.
　　
　　A. where B. when C. which D. who
　　
　　Mexico City, which has a population of over 10 million, is probably the fastest growing city in the world.
　　
　　We will be shown around the city: schools, museums, and some other places, ________ other visitors seldom go.
　　
　　A. what B. which C. where D. when
　　
　　（2）先行词为特定的时间。如：
　　
　　Sir winstom Churchill was British Prime Minister from 1940 to 1945, during which he played a decisive role in the conduct of the Second World War.
　　
　　（3）关系代词as, which代表前一句话的内容时。如：
　　
　　John said he”d been working in the office for an hour, ________ was true.
　　
　　A. he B. this C. which D. who
　　
　　________ is known to everybody, the moon travels round the earth once every month.
　　
　　A. It B. As C. That D. What
　　
　　2. 关系代词的慎用。
　　
　　（1）非限制性定语从句的关系代词不论指人、指物，一般不用that，要用who, whom和which。如：
　　
　　Charlie Chaplin, who died in 1977, is considered one of the greatest and funniest actors in the history of the cinema.
　　
　　（2）关系代词as和which都可代表一句的内容，但which不可置于句首，而as就可以。如：
　　
　　_________ is mentioned above, the number of the students in senior schools is increasing.
　　
　　A. Which B. As C. That D. It
　　
　　3. 引导词也可以是介词+ which (whom, whose)，但在固定的短语里，介词是不可分开而提前用于该结构的。如：
　　
　　Recently I bought an ancient Chinese vase, _________ was very reasonable.
　　
　　A. which price
　　
　　B. the price of which
　　
　　C. its price
　　
　　D. the price of whose
　　
　　He failed the maths exam again, which his parents worried about. （不能说 about which his parents worried）
　　
　　4. 翻译方式与限制性定语从句不同。在译为汉语时，应避免按限制性定语从句的译法翻译，否则就会造成句意不合逻辑。如：
　　
　　Chaplin lived the last years of his life in Switzerland, where he was buried in 1977. 卓别林晚年在瑞士度过，并于1977年在那里去世。（如果按照限制性定语从句的译法翻译，整个句子就不通顺、不合逻辑了。）