英语小问题！

定语从句

1.定语从句的特征

定语从句分为限定性定语从句和非限定性定语从句。限定性定语从句与主句关系紧密，为句中不可缺少的成分，如去掉，则主句意思不完整或不明确。非限定性定语从句与主句关系松散，如去掉，主句内容仍完整。在书面语中，非限定性定语从句一般用逗号与主句隔开。

引导定语从句的关联词包括：

(1)关系代词：that，which，whose，who, whom，as。

(2)关系副词：when，where，why。

关系代词和关系副词在定语从句中都充当一定的句子成分：主语(who，which，that)；宾语(that，which，whom)；定语(whose，of which)；状语(when，where，why)。

2.定语从句中关系词的运用

(1)关系代词。

关系代词的选择一般需从三方面来考虑：①先行词是指人还是指物；②关系代词在从句中作主语、宾语还是定语；③该从句是限定性定语从句还是非限定性定语从句。

关系代词作宾语时，一般可省略。如：

I know that he is a man who/that means what he says. (先行词指人，关系代词在限定性定语从句中作主语)

The man whom/that she met told her a lie. (先行词指人，关系代词在限定性定语从句中作宾语)

The watch which/that was lost has been found. (先行词指物，关系代词在限定性定语从句中作主语)

Here is the material which/that you need. (先行词指物，关系代词在限定性定语从句中作宾语)

He is the only one whose advice she may accept. (先行词指人，关系代词在限定性定语从句中作定语)

(2)关系副词。

关系副词的选择主要看先行词。如先行词为表示时间的名词，如time，day等，则用when；如先行词为表示地点的名词，如place，house，area等，则用where；如先行词为reason，则用why。另外，where = in which，why = for which。例如：

I'll never forget the village where/in which I spent my childhood.

I don't know the reason why/for which he did that.

I'll never forget the day when I first entered the college.

(3)关系代词that和 which的区别。①存在以下情况之一时，只能用that来引导定语从句：

第一，先行词是all，everything，something，anything，little，nothing等不定代词时；

第二，先行词前有next，first，last，only，few，much，some，any，very，no等词修饰时；

第三，先行词前有形容词最高级修饰时。例如：

I've explained everything (that)I can to you. This is the most beautiful city (that)I've ever been to.

②非限定性定语从句一般不用that引导，且关系词不可省略。例如：

His lecture, which bored everyone, ended at last.

The teacher's daughter, whom I met last month, sent me an e-mail.

(4)which和as引导定语从句的区别。在非限定性定语从句中，先行词是整个句子时，一般用which或as来引导。which在从句中可充当主语、宾语等，as在从句中一般只充当主语。which与as引导此类定语从句的区别在于：which只能置于句中或句末，而as的位置比较灵活，既可置于句中、句末，又可置于句首。此外，as引导定语从句时还常和such，so，as或same连用，一般没有明显的先行词，as一般可以译为“正如，就像…那样”。

例如：Water consists of hydrogen and oxygen, which/as is known to all.

As everybody knows, he is a good boy.

Such things as you have described are most important to me.

He is that kinds of man, such as people always meet.

I have the same dictionary as you have.

_____can be seen from the comparison of these figures, the principle involves the active participation of the patient in the modification of his condition.(1999.5)

〔A〕 As〔B〕 What〔C〕 That〔D〕 It

答案为〔A〕。As指代的是后面整句话的内容，引导非限定性定语从句，其他选项只能引导主语从句。本句意为：正如我们从比较这些数字所看到的结果一样，这项规则需要病人在治疗时积极参与。

(5)关系代词在定语从句中有时也作介词的宾语。如果介词被置于关系代词前，一般只用介词+which或介词+whom，而不能用介词+that来引导定语从句。如果介词被置于从句句末，则可用that代替which或whom，且that这时可省去。

This is the coat on which she spent 500 dollars.

One of my classmates whom/that you are familiar with will come today.

Living in the central Australian desert has its problems, _____ obtaining water is not the least.(1994.3)

〔A〕 of which〔B〕 for what〔C〕 as〔D〕 whose

答案为〔A〕。题目中which的先行词是problems，在which引导的非限定性定语从句中作介词of的宾语，这时关系代词要置于介词后面，不能省略。介词of表示所属关系，of which指的是“在这些问题中”。〔B〕 中的for表示原因，与题意不符；〔C〕 和〔D〕 也能引导定语从句，但都与句子的意思不符，所以只能选〔A〕。本句句意为：在澳大利亚中部，沙漠生活面临许多问题，其中汲水是一个很严峻的问题。

2.定语从句与同位语从句的区别

同位语从句大多由连接词that引导，常跟在下列名词后面，如fact，idea，opinion，news，hope，belief等。同位语从句用来解释说明这些名词的具体含义和内容。定语从句对所修饰的名词加以修饰限定，即说明其为此人(事物)而非彼人(事物)。如：

We are familiar with the idea that all matter consists of atoms.(同位语从句)

The news that we are invited to the party is very encouraging.(同位语从句)

This is the best article that has been written on the subject. (定语从句)

4.定语从句与what引导的名词性从句的区别

what只能引导名词性从句，在从句中充当主语、宾语或表语，但总是包含着定语从句的含义，很容易与定语从句混淆。定语从句的引导词前面都会有先行词，而what前面则没有任何先行词，此时what=先行词+that。试比较：

He always means what he says.

That's the only thing that he says.

That's what I want to say.

That's all (that) I want to say.

This is what I can give you.

This is all the money that I can give you.