2010年12月大学英语四级考试常用语法精选(12)

　　Ⅴ 连词

　　并列连词

　　表示意义的引申: and, both…and, not only…but(also), as well as, and …as well, neither…nor

　　表示选择: or, either…or

　　表示转折: but, while, whereas, yet, however/nevertheless(也可认为是副词)

　　表示因果: for, so, therefore, hence

　　从属连词

　　表示时间: when, while, as, after, before, since, until(till), as soon as, once

　　表示原因: because, as, since, now that, seeing that

　　表示条件: if, unless, in case, provided(that), suppose, as long as, on condition (that),

　　表示其他关系: (al)though, than, as/so…as, lest, in order that, so…that

　　Ⅵ 定语从句

　　限制和非限制性定语从句: 限制性定语从句是名词词组不可缺少的一个组成部分, 去掉了会造成病句或意义不明确; 非限制性定语从句属于补充说明性质, 去掉了不会影响主要意义, 通常用逗号与它的先行词分开.

　　The boys who wanted to play football were disappointed when it rained.

　　The boys, who wanted to play football, were disappointed when it rained.

　　如果定语从句的先行词是专有名词, 或是带有形容词性物主代词(my, his, etc)或形容词性指示代词(this, that, etc)作限定词, 其后的定语从句通常都是非限制性的:

　　Mary Smith, who is in the corner, wants to meet you.

　　Her mother, who had long suffered form arthritis, died last night.

　　All these books, which have been donated by visiting professors, are to be used by the postgraduates.

　　在非限制性定语从句中只能用who/whom指人, 用which指物,通常不用that替代.

　　My father, who had been on a visit to America, returned yesterday.

　　All the books, which had pictures in them, were sent to the little girl.

　　定语从句的引导词

　　that, who, whom: 非限制性定语从句, 如果修饰人, 一般用who, 有时用that (作主语时用who较多). 如果关系代词在从句中作宾语, 就应当用宾格 whom 或that, 但在大多数情况下都可以省略掉, 在口语中可用who代替whom.

　　Here is the man (whom) you’ve been looking for.

　　He is a man (that) you can safely depend on.

　　The people (who/that) you were talking to were Swedes.

　　There are some people here who I want you to meet.

　　但在介词后只能用whom:

　　This is the man to whom I referred.

　　但在口语中一般都把介词放到句子后面去, 这时可用that, 但省略时更多一些.

　　Have you met the person about whom he was speaking?

　　Have you met the person (that) he was speaking about

　　The girl to whom I spoke is my cousin.

　　The girl (who/that) I spoke to is my cousin.

　　限制性定语从句如果修饰“物”, 用关系代词that的时候较多, 也有时用which.. 当这个代词在从句中是用作宾语时, 在绝大多数情况下都是省略的, 特别是口语中(尤其是当被修饰的词是all, everything等词时):

　　Have you everything you need?

　　(Is there) anything I can do for you?

　　All you have to do is to press the button.