定语从句语法教学

高大伟

在高中英语语法教学中，定语从句是很重要的一部分内容。高一上册课本整整3个单元（4～6）安排的全是定语从句。但每当讲到定语从句时，总有一些学生把这部分内容混淆起来，做练习题和考试时很容易出错误。

定语从句定义由关系代词或关系副词引导的句子用来修饰主句中的某一个名词或代词的从句起定语的作用，叫定语从句。定语从句所修饰的词叫先行词，定语从句跟在先行词后面。

定语从句的构成方法关系代词或副词+陈述句语序，关系代词有who，whom，whose，which，that，as等，关系副词有when，where，why等。关系代词有双功能，一方面代表前面所修饰的先行词，把从句和先行词连接起来；另一方面引出从句并在从句中充当句子的成分。

定语从句的种类有2类：限制性定语从句，非限制性定语从句。下面通过举例来总结一下2类定语从句的区别。1）The book which/that you lent me is very interesting.2）Do you remember the teacher who taught us English at middle school？3）Mr. Zhang, who came to see me yesterday, is an old friend of my fathers.4）We walked down the village street, where they were having market day.5）He gave his mother a color TV set for her birthday, which pleased her a lot.6）They are coming back to us, which means that they have been refused else where.

以上例句中的1）和2）2句为限制性定语从句；3）、4）、5）、6 ）4句为非限制性定语从句。

1）如果定语从句对先行词具有限制作用，使该词的含义更具体、更明确，这种属于限制性定语从句；定语从句有时跟先行词的关系并不十分密切，只是做一些附加说明，不起限制作用，这种属于非限制性定语从句。限制性定语从句中的从句部分不能省略，否则句子的意义就不完整了。

2）限制性定语从句与主句之间不能用逗号隔开；非限制定语从句往往用逗号与主句隔开。

3）有时非限制性定语从句修饰的不是前面某个词，而是代表整个句子所讲的内容，通常用逗号与主句隔开，如例句5）、6）中that不能引导非限制性定语从句。

在非限制性定语从句中，as 与 which 的用法及区别1)as引导的非限制性定语从句既可以放在句首也可以放在句末；which引导的非限制性定语从句只能放在句末。如：He was a foreigner, as I know from his accent./As is expected, he has passed the exam./I said nothing, which made him very angry.2) 当主句和从句意义一致时，用as，反之用which。3）当非限制性定语从句为否定句时，常用which引导。如：Tom drinks a lot every day, which his wife doesnt like at all.

“介词+关系代词”和由关系副词引导的定语从句1）when指时间，在定语从句中做时间状语。如:I still remember the day when (on which) I first came to Beijing.2）where指地点，在定语从句中做地点状语。如：That is the house where (in which) he lived ten years ago.3）why指原因，在定语从句中做原因状语。如：I know the reason why (for which) he was so angry.4）含有介词的短语一般不拆开，介词仍然放在动词后面。如：Is this the book (which/that) he was looking for./The babies (whom/that) the nurses are looking after are very healthy.

最常见的3种错误由于定语从句的结构和用法比较复杂，初学者在使用时往往会犯一些错误，最常见的有3种。1）在定语从句中加了多余的宾语。误：Some of the boys I invited them didnt come.正：Some of the boys I invited didnt come.应删去them，因为从句的宾语省略了whom，who或that.2）在定语从句中谓语动词的单复数弄错。误：This is one of the rivers in China which flows northward.正：This is one of the rivers in China which flow northward.flows应改为flow，因为which 指rivers而不是指one。3）省略定语从句中做主语的关系代词。误：Children eat a lot of sugar often get bad teeth.正：Children who/that eat a lot of sugar often get bad teeth.定语从句中应加上做主语的关系代词who或that.

（作者单位：河北省滦县第十中学）