重点内容如下：
①because语气最强，用于回答why的提问，可与强调词only,just 以及否定词not 连用。但不可以与so连用。如You shouldn’t get angry just because some people speak ill of you.另外注意与not连用时否定的转移。He didn’t do such a thing because he was afraid of his wife.他并不是因为怕他的妻子才做这样的事。
Cf:He didn’t do such a thing,because he was afraid of his wife.因为怕妻子，他没有做这样的事。
because引导的从句可以被强调：
It was because she wanted to study abroad that she entered for TOEFL
②as语气较弱，since语气也较弱，但比as正式一些,所说明的原因比较明显或是已知的事实，多用于口语中，所以不应该强调。常置于句首。
As all the seats were full,he stood there.
Since you are going,I’ll go,too.
③for虽解释为“因为”但只是一个并列连词，它引导的是并列句，不是原因状语从句。
The day was short,for it was December.
3.地点状语从句
由下列连词引导:where,wherever,anywhere,everywhere。
Anywhere he went,he got warm welcome.
The girl takes the doll with her everywhere she goes.
Wuhan lies where the Yangtze and the Han River meet.武汉位于长江和汉水汇合处。
Where there is a will, there is a way.有志者，事竟成。
You’d better make a mark where you have any questions.
哪儿有问题，你最好在哪儿做个记号。(这里where引导的从句不是定语从句)
4.结果状语从句
由下列连词引导：that，so…that，so that(从句中不带情态动词)，such…that，with the result that等。
注意以下几种结构：
①so+adj/adv+that…
②such(a/an+adj)+n+that…
③so+adj+a/an+n+that=such a/an+adj+n+that…
④so many/much/few/little(少)+n+that…
注意以上结构与定语从句so/such…as的区别。
This is such an interesting/so interesting a film that/as everyone wants to see it/(it).
He didn’t plan his time well so that/so he didn’t finish the work in time.
他没把时间计划好，结果没按时完成这项工作。
We left in such a hurry that we forgot to lock the door.
我们走得匆忙，把门都忘了锁了。
The village is so small that it cannot be shown in the map.
这村子太小，所以这地图上没有。
Jenny is such a clever girl that all the teachers like her very much
= Jenny is so clever a girl that all the teachers like her very much
Jenny是如此聪明的女孩，以至老师们都非常喜欢她。
I have had so many falls that I am black and blue all over.
我摔了许多跤，以至于浑身青一块紫一块
He has so few friends that he often feels lonely.
他朋友很少，所以经常感到孤独。
I had so little money then that I couldn’t afford a little present.
我当时囊中羞涩连一份小小礼物都买不起
5.目的状语从句
由下列连词引导：so that,in order that,for fear that等。目的状语从句的谓语动词常与情态动词can, could, may, might, should连用目的状语从句的谓语动词常与情态动词can, could, may, might, should连用。
(so that也可用来引导结果状语从句，但从句中不带情态动词)
Let’s take the front seats (so) that we may see more clearly.
我们坐前排吧，这样我们看得更清楚些。
School was closed early in order that the children might go home ahead of the storm.
早点儿放学是为了让孩子们在暴风雨到来之前回家。
He took the name down for fear that he should forget it.
他把名字写下省得忘了。(该从句中一般用情态动词should+动词原形，或省略should)
Better take more clothes in case the weather is cold.
最好多带些衣服以防天气会冷。
注意：so that引导的目的状语从句只能放在主句之后，in order that 引导的目的状语从句可以放在主句之前或之后。
6.条件状语从句
分为真实条件句和非真实条件句(用在虚拟语气中)。
表示条件的状语从句可以由if(如果),unless(除非), in case(万一), so /as long as(只要), as/ so far as(就……而言), on condition that(条件是……)suppose(假设)supposing(假设)(仅用在问句中)
等词或词组引导。一般情况下当主句是将来时的时候，从句要用一般现在时。
As/So long as we don’t lose heart, we’ll find a way to overcome the difficulty.
只要我们不灰心，我们就能找到克服困难的方法。
Send us a message in case you have any difficulty.万一你有什么困难，请给我们一个信儿。
If you leave at 6 o’clock tomorrow morning, you’d better get to bed now.
如果你明早6点钟走，你最好现在就上床。
We’ll let you use the room on condition that you keep it clean and tidy.
只要你能保持整洁，我们可以让你使用这个房间。
As/So far as I know, he is an expert on DNA.据我所知，他是一个DNA专家。
He’ll accept the job unless the salary is too low/ if the salary is not too low.
他会接受这项工作的，除非薪水太少/如果薪水不太少的话。
Suppose/Supposing we can’t get enough food, what shall we do?
假设我们弄不到足够的食物，那我们怎么办?
7.让步状语从句
由下列连词引导：although,though,as,even if, even though,while,whether…or,whoever,whatever,however,
no matter+疑问词等。
We won’t be discouraged even if(=even though) we fail ten times.
我们就是失败十次也不泄气。
It was an exciting game, though / although no goals were scored.
那是一场精彩的球赛，尽管一个球都没进。
Whether you believe it or not, it’s true.不管你信不信，这是真的。
However (=No matter how) expensive it may be, I’ll take it.无论它有多贵，我也要买下它。
Don’t let them in, whoever(=no matter who) they are.不管他们是谁，别让他们进来。
No matter what I say or how I say it, he always thinks I’m wrong.无论我说什么或怎么说，他总认为是我错。
注意以下几点：
①although,though引导让步状语从句时，主句前不能用but,但可以加yet,stil。
He refuses help although he has many friends who want to offer all kinds of help.
②as引导让步状语从句时，必须用前置结构，通常是从句中的表语、状语或动词原形放在句首，放在句首的名词前的冠词要去掉。
Child as(though)he is, he knows a lot.(注意在child前不要用冠词)
Much as I like it, I won’t buy.
Try as he would, he couldn’t lift the heavy box.
