若从句前有逗号，一般为结果状语从句，如果从句中有情态动词，通常则为目的状语从句。如：
They started out early, so that they didn’t miss the train.
他们早早就出发了，所以没误火车。(结果状语从句)
They started out early so that they would not miss the train.
他们早早出发是为了不误火车。(目的状语从句)
(2) so...that引导的结果状语从句
so...that“如此……以致”，that在非正式文体中可以省略，so后面接形容词或副词。如：
She spoke so fast that nobody could catch what she was saying.
她说话如此之快竟没有人听出来她在讲什么。
There is so little time left that I have to tell you about it latter.
现在剩下的时间不多了，我只好以后再给你讲这件事。
(3) such...that引导的结果状语从句
引导结果状语从句的such...that的具体内容是：such+a/an+形容词+名词+that从句。
其中的名词可以是可数名词的单数或复数，也可以是不可数名词。
such+a/an+形容词+单数名词+that从句可换成so+形容词+a/an+单数名词+that从句。如：
The Japanese student made such rapid progress that he soon began to write article in Chinese.
那个日本留学生进步很快，不久就开始用中文写文章了。
The professor told us such a funny story that all the students laughed．
(＝The professor told us so funny a story that all the students laughed.)
教授讲了个很有趣的故事，(以致于)所有的学生都笑了起来。
(4) such that引导的结果状语从句
such that引导的结果状语从句多用于正式文体，主句为“主—系—表”句型。如：
The force of the explosion was such that it blew out all the windows.
爆炸的力量很大，所有的窗户都被炸掉了。
His anger was such that he lost control of himself.
他气得不能克制自己的感情。

状语从句 - 条件状语从句 
(1) if引导的条件状语从句
if可引导非真实条件状语从句(见“虚拟语气”)和真实条件状语从句。如：
If he said that，he can’t be telling the truth.
如果他说了那样的话，他不可能是说实话。
(2) unless引导的条件状语从句
unless引导的是否定条件状语从句，在意义上相当于if...not，而且语气较强，一般不用于虚拟语气。如：
You’ll be late unless you hurry.
你会迟到的，如果不赶快的话。
(3) if only引导的条件状语从句
if only在引导条件状语从句时意为“只要；如果”。如:
I’ll let you use the car if only you keep it in good condition.
只要你把车保养好，我就让你用。
(4) as/so long as引导的条件状语从句
as/so long as意为“只要；如果”。如：
As long as it doesn’t rain, we can play.
只要不下雨我们就能玩。
(5) provided (that)/providing (that)引导的条件状语从句
provided (that)/providing (that)意为“如果；只要”。如：
I will agree to go provided’ providing (that my expense are paid.)
假如为我负担费用，我就同意去。
Providing you promise not to tell anyone else I’ll explain the secret.
状语从句 - 让步状语从句
(1) although/though引导的让步状语从句
although和though，都作“虽然；尽管”解，通常可以换用，although的语气较重。
如果要强调“但是”语气，可使用yet，still或nevertheless来表示“但是”、“依然”或“然而”之意。
Although they have been talking for a long time, he cannot make her believe him.
虽然和她谈了半天，他还是不能让她信任自己。
(2) even if引导的让步状语从句
even if “即使，纵然”，从句表示的是尚未发生的动作或存在的情况。如：
Even if it rains tomorrow，we won’t change our plan.
即使明天下雨，我们也决不改变计划。
Even if I failed again, I will not give up the experiment.
即使我再次失败，我也决不会放弃实验。
(3) even though引导的让步状语从句
even though“虽然，尽管”，从句所表示的是已经发生的动作或存在的情况，通常可以和although/though换用。如：
Even though I didn’t understand a word，I kept smiling.
即使我一个字也不懂，我还是保持微笑。
Even though you say so，I do not believe it.
即使你这样说，我也不信。
(4) much as引导的让步状语从句
much as“虽然，尽管”，通常可以和although/though换用：
Much as I’d like to，I can’t come.
我虽然很想来，但是来不了。
Much as I admire his courage，I don’t think he acted wisely.
我虽然佩服他的勇气，但我认为他这样做是不聪明的。
(5) while引导的让步状语从句
while“虽然，尽管”，多用于正式文体，通常可换作although/though。如：
While I understand your point of view，I do not share it.
我虽了解你的观点，但不敢苟同。
While I sympathize，I really can’t do very much to help.
虽然我很同情，但我确实帮不了什么忙。
(6) whatever/No matter what引导的让步状语从句
whatever和no matter what用法相同，都作“无论什么”解，后者多用于非正式文体。如：
Whatever/No matter what he says，don’t go.
不管他说什么，你都不要走。
We are determined to fulfill the task，whatever/no matter what happens.
不管发生什么了，我们决心完成任务。
(7) whichever/no matter which引导的让步状语从句
whichever和no matter which用法相同，都作“无论哪个”解，后者多用于非正式文体。如：
Whichever/No matter which you buy， there is a six-month guarantee.
不论你买哪个，都有六个月的保修期。
Whichever/No matter which of the two men had stolen her purseBarbara was determined to find them.
不管这两个人是谁偷了她的钱包，芭芭拉决心找到他们。
(8) whoever/no matter who引导的让步状语从句
whoever和no matter who用法相同，都作“无论谁”解，后者多用于非正式文体。如：
You can’t come in， whoever you are.
不管你是谁，都不能进来。
Whoever/No matter who wants to speak to me on the phone, tell him I’m busy.
不管谁要我接电话， 就说我现在正忙着呢。
(9) whereverno matter where引导的让步状语从句
wherever和no matter where用法相同，都作“无论在（或到）哪里”解，后者多用于非正式文体。如：
Wherever/No matter where you go, I’m Right Here Waiting fo ryou.
无论你到哪里，我都依然在这里等着你。
(10) however/no matter how引导的让步状语从句
however和no matter how用法相同，都作“无论如何……”解，后者多用于非正式文体。
However much you regret doing that， there is nothing you can do about it now.
无论你可能多么懊悔你曾经做过的事，现在也无济于事了。
However high it may be，it can’t reach the sky.
它不论有多高，也高不到天上去。
(11) whenever/no matter when引导的让步状语从句
whenever和no matter when用法相同，都作“无论何时”解，后者多用于非正式文体。如：
Whenever I’m unhappy，he cheers me up.
每当我不高兴时，他就给我鼓劲儿。
(12)(no matter) whether...or引导的让步状语从句
whether...or和no matter whether...or用法相同，都作“不论……还是”解，后者的语气强一些。如：
When It Rains or not, we’re playing football on Sunday.
无论下不下雨，我们星期天一定踢足球。
(13) as引导的让步状语从句
as在引导让步状语从句时作“虽然；尽管”和“即使”解，但是它不位于句首，在它前面的可以是形容词、名词、副词等。如：
Strong as you maybe, you cannot lift it.
虽然你可能很有力气，你却无法把它提起来。
Late as it was, they continued to study.
时间尽管不早了，他们仍继续学习。

状语从句 - 方式状语从句
(1) as引导的方式状语从句
as在引导方式状语从句时意为“以……方式；如同……那样”，从句有时是省略句。如：
Do as I say. 要照我说的做。
I did just as you told me. 我正是照你说的办的。
Air is to man as water is to fish. 空气之于人犹如水之于鱼。
(2) as if/as though引导的方式状语从句
as if和as though的用法相同，都作“好像，仿佛”解。如：
二者引导的状语从句往往用虚拟语气，表示与事实相反。as if比as though更为常用。
但也可用陈述语气，表示所说的情况是事实或实现的可能性较大。如：
They looked at me as if ‘as though I were mad.
他们瞧着我好像我发疯了似的。
They look as if/as though they know each other.
他们看来好像互相认识。

状语从句 - 比较状语从句
(1) as...as 引导的比较状语从句
as...as表示同级比较，主句中用形容词或副词的原级形式，从句常常为省略句。如：
We were as fortunate as them (they were)
我们和他们一样幸运。
I hope she will make as much progress as you (have done).
我希望她将取得和你同样的进步。
(2) not so/as...as 引导的比较状语从句
not so/as...as表示同级比较，主句中用形容词或副词的原级形式，从句常常为省略句。如：
That’s not so/as simple as it sounds.
那件事情不像听起来那么简单。
(3) than引导的比较状语从句