语法继续

as在定语从句中的用法

1、常用于下列结构：

（1）so…as; 

eg. He is so clever a boy as all of us like very much.他是一个我们大家都非常喜欢的聪明的男孩。

注意：本句中，先行词a boy 在定语从句all of us like very much中作like的宾语，而且前面有so 修饰，所以关系代词用了as。

（2）such… as

eg. He’s not such a fool as he looks. 他并不像看上去的那样愚蠢。

（3）as …as

eg. He smokes as expensive a cigarette as he can afford. 他抽一种他买得起的最贵的烟

（4）the same … as

eg. I live in the same place as Tom does. 我和汤姆住在同处。

注意：the same…as 表示同一类，不同一个；the same…that 表示同一个

eg. This is the same bike that I lost yesterday. (同一事物)

This is the same bike as I lost yesterday. （同类事物）

2、as与which的区别

（1）位置不同

as可放在主句后，主句前或主句中间；

which只能放在主句后。

（2）as起连接作用，表达说话人的观点、看法，并指出主句内容的根据或出处，意为“正如，正像”。

Which相当于并列句，可以用and this来代替，意为“这一点，这件事’”。

注意：as常用于下列结构：

a）as we know/ as is known to all

eg. As we all know, life is not perfect.众所周知的是，生活并不完美。

b）as we all can see

eg. This machine, as we all can see, has stopped operating.  这台机器正如我们都能看到的，已经停止转动。

c）as has been said before/above

eg. As has been said before, reading is a good way in learning English.  正如以前所说，朗读是学英语的一种好方法。

d）as might be excepted,

eg. Freddie, as might be expected, was attending the conference. 弗雷迪在参加会议，这是可以预料到的。

e）as is often the case

eg. He was late for school, as is often the case.他又迟到了，他常常这样。

以上几种结构中，一般不能用which代替as。

（3）在从句中作主语时，which既可作系动词be的主语也可作实义动词的主语；而as只可作系动词be的主语。

eg.He merried her , which/as was natural..

He saw the girl， which delighted him.