英语语法第13期——than（as和but作准关系代词得用法）

than, as, but作准关系代词的用法

关系代词通常是用来引导定语从句的，than, as和but除了做基本连词外还可以作准关系代词，但是与which，who,that等关系代词不同，than, as和but引导的定语从句与典型的定语从句不太相像，因此称它们为准关系代词。

Than,as,but作准关系代词条件是：前面必须有先行词（名词）

例：

I have more money than you do (我比你有钱)

He has as much money as I do （他和我的钱一样多）

There is nothing but he knows（没有什么他不知道的）

我们分别进行详细说明：

1. Than 作准关系代词的用法。

Than 之前若有名词，则than = than + the + 前面的名词 + 关系代词（who, whom, which）,因此可以将than 视为关系代词。Than 作准关系代词通常出现在more …than,less…than, fewer…than等结构中，且在从句中可以充当主语，宾语和be动词后得表语。

例1. I have more moneythan is needed.（than作从句的主语）

= I have more money than the money which is needed

（我现有的钱比所需要的多）

例2. I have more money than he needs（than作从句的宾语）

I have more money than the money whichhe needs

（我现有的钱比他所需要的多）

例3. heis a better student than you（ are ）.(than 作从句的表语)

2. As 作准关系代词的用法。、

as之前若有名词，则as = as + the + 前面的名词 + 关系代词（who, whom, which）,因此可以将as 可视为关系代词，并在所引导的从句中作主语，宾语和be动词之后的表语。但只用于下列短语中：

注意：

① such + n. 之后不可用like（像）加以修饰。

Such a man like him is bad. (错)

Such a man as him is bad.（对）

② as 可替代主句。单独使用as时，as也可以作关系代词，等于which，用来代替整个主句。

He is nice, which is known to us

= he is nice , as is known to us(他人很好，我们都知道)

③ as引导的从句可置于主句的前后，而which引导的从句只能置于主句之后。

例. He is nice, as we all know= as we all know, he is nice

④只能与单数可数名词使用的结构。

3. But 作为准关系代词的用法。

But 作为准关系代词时，只用于“no + n.”之后，此时but等于who(whom, which )…not.

即there is no + 名词 + who(whom, which, that)…not

= there is no + 名词 + but……

定语从句中有be 动词保留be动词

例：thereis no one who is not interested in it.

= there is no one but is interested in it(没有人不对他感兴趣)

定语从句中有助动词（can,will,may,should…）保留该助动词。

There is nothing that he can not do

=There is nothing but he can do（没有什么事是他做不来的）

定语从句中有do,does和did等助动词时，先去掉助动词，在依时态人称将之后的动词还原。

There is no book which he doesn’t like to read

= There is no book but he likes to read.

这期就到这里就结束了，我们下期再见哦！