从句是英语学习中一种非常常见的句型，在教师招聘考试也是作为重点考点之一，今天小编就给大家总结一下从句的相关知识。

1.名词性从句

主要包括主语从句、宾语从句、表语从句和同位语从句。一般由that 引起,也可由who, what, when, why, which, whom, whether, how 引起。

主语从句很多情况下都可以放到句子后面,而用代词it作形式上的主语。

由名词性关系代词whatever, whoever, whichever 等引起的宾语从句。

whether and if 都能引导从句, 但用法有所不同。当主语从句直接位于句首时,应用whether,而不用if。 Whether 后能接or not, 但if 不能。

Whether he will come or not is not known.

在名词reason后的表语从句须用that引导, 不可误用 because。

The reason why he is often late for class is that he has the bad habit of getting up late in the morning.

2.定语从句

引导定语从句的关系词有who, whom, whose, that, when, wher, why and which。 在非限制定语从句中, 只可用which, who, whose, wher , when, 如果指代前面整个句子, 多用which。

当引导定语从句的先行词前有all, any, no, little, much, very first 等词, 或先行词前为形容词高级所修饰时,或先行词为all, anything, nothing, something, everything 时,从句的引导词只能用that。

as 可做引导词引导定语从句, 多和such, the same 连用。as引导的定语从句也可修饰整个句子, 既可放在先行词后,也可放在句子开头。

介词+which/whom/whose从句。

代/名+介词+which 从句。

3.状语从句

修饰主句中的动词, 形容词和副词, 通常有从属连词引导, 按其意义和作用可分为时间、地点、条件、原因、让步、目的、结果、方式、比较等。

时间状语从句:

(1) 常见连词有 after, as, before, once, since, till, (not)until, when, whenever(no matter when), while, as long as, as soon as...

(2) no sooner...than, hardly(scarcely, barely)...when，刚做……就……

(3) 还有 immediately, directly, instantly, the moment, the minute, the instant, the second, every time...

地点状语从句: 一般用wher或 wherver 引导。

条件状语从句:if, unless, so long as, provided that, supposing that, on condition that, in the event that, in case that...

原因状语从句: 从属连词有because, as ,since, for, now, that, in that, seeing that, considering that(鉴于,由于)。

让步状语从句:

(1)even if, though, even though, while(尽管)，no matter what/how/which, however, whatever, whichever, however...

(2) 由as 引起的让步从句, 语气较强烈,被强调的词须放在句首。

(3) whether...or...,不管……或……

结果状语从句: so that, so...that, such...that。

目的状语从句: so that, in order that, for fear that, in case。

方式状语从句: as, just as, as if 如同……一样。

比较状语从句:

(1) as...as, not so/as...as

(2) 比较级+than, so much/a lot more than

(3) no more...than, less...than

(4) the more...the more