「状语从句」有哪些？
什么是状语从句我们同学一般很清楚，但说到状语从句的种类，就不是很清楚，只能说出几种比较常见的状语从句，比如时间，条件，原因这些状语从句，那具体的状语从句有哪些呢，其实是以下九种。1.时间状语从句：
有以下从属连词可以引导时间状语从句，比如when, while, as, as soon as, the moment, long before, until等。 I loved history when I was at school. As soon as we have that transcript, we will shoot that around, as well.2.地点状语从句：
一些从属连词比如where，wherever可以引导地点状语从句。 Where people were concerned, his threshold of boredom was low.3.条件状语从句：
以下从属连词比如if，unless, as long as可以引导条件状语从句。 If he improved his IT skills, he would easily get a job. You won’t get paid for time off unless you have a doctor’s note.4.原因状语从句：
像because, as, since, in that, now that, considering that。 He is called Mitch, because his name is Mitchell. I’m forever on a diet, since I put on weight easily.5.让步状语从句：
以下从属连词比如although, though, even though, while, whether等可以引导让步状语从句。 Although he is known to only a few, his reputation among them is very great. Whether they say it aloud or not, most men expect their wives to be faithful.6.目的状语从句：
so that可以引导目的状语从句。 They try to rehabilitate them so that they can live out their remaining years happily.7.结果状语从句：
so…that可以引导结果状语从句。 I studied so hard that I got the first place in the race.8.方式状语从句：
just as, as if, as though可以引导方式状语从句。 I can remember our wedding as if it were yesterday.9.比较状语从句：
more than/as…as… People are not as honest as they once were.「状语从句」考什么？
既然我们已经了解了状语从句的形式，那么SAT语法考试中状语从句通常会考察什么呢？首先会考察状语从句的标点使用情况。比如下面这道题：
拿到这道题目以后，我们同学肯定会说，这个状语从句在哪里呢，我怎么没有找到呢？其实这个状语从句就比较隐晦，这是一个倒装切省略了连词的状语从句。be it= whether it is,所以我们就知道原来“be it by the passing of time, natural disasters, or human error” 就是后置的状语从句，实际上是“whether it is by the passing of time, natural disasters, or human error”。
可是这个状语从句是以be it…的形式出现的，没有了连词，为了能够和主句区分开来，所以需要一个标点符号，上面说了，如果加标点可以加逗号或者破折号，那么选项里没有逗号，只有破折号，所以这道题选D。
如果状语从句前置，这时候状语从句和主句之间需要标点吗？比如这道题：
这道题里面首先是由while引导的状语从句放在了句首，然后后面有一个主句即“others look to the past,…”，首先我们知道两句话中只能有一个连词连接，所以不能出现两个连词，所以排除AD；那么问题来了，如果状语从句置于句首，要不要加标点呢，其实还是要加的，所以选C，如果不加标点，那么就没有可以明显可以把两个句子断开的标志，所以必须加上这个逗号。所以，我们可知状语从句置于句首，一定加逗号。
其次，另外一个关于状语从句的考点就是有哪些从属连词可以引导状语从句，做题的时候可以辨别出来原来这里考察的是状语从句，需要这样一个连词，比如下面这道题。
推荐阅读
