高大偉

在高中英語語法教學中，定語從句是很重要的一部分內容。高一上冊課本整整3個單元（4～6）安排的全是定語從句。但每當講到定語從句時，總有一些學生把這部分內容混淆起來，做練習題和考試時很容易出錯誤。

定語從句定義由關系代詞或關系副詞引導的句子用來修飾主句中的某一個名詞或代詞的從句起定語的作用，叫定語從句。定語從句所修飾的詞叫先行詞，定語從句跟在先行詞后面。

定語從句的構成方法關系代詞或副詞+陳述句語序，關系代詞有who，whom，whose，which，that，as等，關系副詞有when，where，why等。關系代詞有雙功能，一方面代表前面所修飾的先行詞，把從句和先行詞連接起來；另一方面引出從句并在從句中充當句子的成分。

定語從句的種類有2類：限制性定語從句，非限制性定語從句。下面通過舉例來總結一下2類定語從句的區(qū)別。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句為限制性定語從句；3）、4）、5）、6 ）4句為非限制性定語從句。

1）如果定語從句對先行詞具有限制作用，使該詞的含義更具體、更明確，這種屬于限制性定語從句；定語從句有時跟先行詞的關系并不十分密切，只是做一些附加說明，不起限制作用，這種屬于非限制性定語從句。限制性定語從句中的從句部分不能省略，否則句子的意義就不完整了。

2）限制性定語從句與主句之間不能用逗號隔開；非限制定語從句往往用逗號與主句隔開。

3）有時非限制性定語從句修飾的不是前面某個詞，而是代表整個句子所講的內容，通常用逗號與主句隔開，如例句5）、6）中that不能引導非限制性定語從句。

在非限制性定語從句中，as 與 which 的用法及區(qū)別1)as引導的非限制性定語從句既可以放在句首也可以放在句末；which引導的非限制性定語從句只能放在句末。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) 當主句和從句意義一致時，用as，反之用which。3）當非限制性定語從句為否定句時，常用which引導。如：Tom drinks a lot every day, which his wife doesnt like at all.

“介詞+關系代詞”和由關系副詞引導的定語從句1）when指時間，在定語從句中做時間狀語。如:I still remember the day when (on which) I first came to Beijing.2）where指地點，在定語從句中做地點狀語。如：That is the house where (in which) he lived ten years ago.3）why指原因，在定語從句中做原因狀語。如：I know the reason why (for which) he was so angry.4）含有介詞的短語一般不拆開，介詞仍然放在動詞后面。如：Is this the book (which/that) he was looking for./The babies (whom/that) the nurses are looking after are very healthy.

最常見的3種錯誤由于定語從句的結構和用法比較復雜，初學者在使用時往往會犯一些錯誤，最常見的有3種。1）在定語從句中加了多余的賓語。誤：Some of the boys I invited them didnt come.正：Some of the boys I invited didnt come.應刪去them，因為從句的賓語省略了whom，who或that.2）在定語從句中謂語動詞的單復數弄錯。誤：This is one of the rivers in China which flows northward.正：This is one of the rivers in China which flow northward.flows應改為flow，因為which 指rivers而不是指one。3）省略定語從句中做主語的關系代詞。誤：Children eat a lot of sugar often get bad teeth.正：Children who/that eat a lot of sugar often get bad teeth.定語從句中應加上做主語的關系代詞who或that.

（作者單位：河北省灤縣第十中學）