一、时间状语从句：是由when, as, while, after, before, since, until, as soon as 等从属连词引导的状语从句。时间状语从句中的谓语动词不能用一般将来时，只能用一般现在时表示将来发生的动作或存在的状态。
如:I will call you as soon as I arrive there.
While he was doing his homework, the telephone rang.
As he walked along（沿着走） the lake, he sang happily
二、原因状语从句： because, since, as和for都表示原因。常常令我们不知该用哪个好。我们来比较一下。because语势最强，回答why提出的问题，用来说明人所不知的原因。当能够很明显的看出原因或人们已知原因，就用as或since。如：I don't like that coat,because the color looks terrible. 由because引导的从句如果放在句末，且前面有逗号，则可以用for来代替。但如果不是说明直接原因，而是多种情况加以推断，就只能用for。
如：He is not here, because / for his mother is ill.
As it is raining, we shall not （不得；不应该）go the zoo.
Since you can’t answer the question, I’ll ask someone else.
三、目的状语从句：表示目的状语的从句可以由in order that, so that,等词引导。 如：You must raise your voice so that/in order that everybody can hear you clearly.
四、结果状语从句：结果状语从句常由so...that 或 such...that引导，要掌握和区分这两个句型，首先要了解so和such后面分别跟什么词。such是形容词，修饰名词或名词词组，so是副词,只能修饰形容词或副词。so 还可与表示数量的形容词many, few, much, little连用，形成固定搭配。
如：The box is so heavy that I can't carry it.
She is such a good teacher that everybody likes her.
My pencil fell under the desk, so that I couldn’t see it.
五、让步状语从句：是由though, although 引导的状语从句。though, although 和 but不能同时使用。
Although it rained, they had a good time.
Though he is young, he knows a lot.
一. 单项填空1-5.ACBCA 6-10.CDCCA 11-15.BCBAC 16-20.BADCB
1. _______ he’s old, he can still carry this heavy bag.
A. Though B. Since C. For D. So
2. ---Do you know if he _______ to play basket ball with us?
---I think he will come if he ______ free tomorrow.
A. comes; is B. comes; will be C. will come; is D. will come; will be
3. In the zoo if a child _____ into the water and can’t swim, the dolphins may come up ______ him.
A. will fall; to help B. falls; to help
C. will fall; help D. falls; helping
4. I don’t remember ________ he worked in that city when he was young.
A. what B. which C. where D. who
5. We will stay at home if my aunt ________ to visit us tomorrow.
A. comes B. come C. will come D. is coming
6. The police asked the children _______ cross the street ________ the traffic lights turned green.
A. not; before B. don’t; when C. not to; until D. not; after
7. I was late for class yesterday _______ there was something wrong with my bike.
A. when B. that C. until D. because
8. I’ll go swimming with you if I ________ free tomorrow.
A. will be B. shall be C. am D. was
9. In the exam, the ________ you are, ______ the _______ mistakes you will make.
A. careful; little B. more careful; fewest
C. more careful; fewer D. more careful; less
10. You should finish your lessons _______ you go out to play.
A. before B. after C. when D. while
11. I hurried _____ I wouldn’t be late for class.
A. since B. so that C. as if D. unless
12. When you read the book, you’d better make a mark _______ you have any questions.
A. which B. that C. where D. though
13. The teacher raised his voice _______ all the students could hear him.
A. for B. so that C. because D. in order
14. He took off his coat _______ he felt hot.
A. because B. as C. if D. since
15. It is ______ that we’d like to go out for a walk.
A. a lovely day B. too lovely a day
C. so lovely a day D. such lovely a day
16. Mary had ______ much work to do that she stayed at her office all day.
A. such B. so C. too D. very
17. _______ I felt very tired, I tried to finish the work.
A. Although B. Because C. As D. As if
18. ______ the day went on, the weather got worse.
A. With B. Since C. While D. As
19. ______ well you can drive, you must drive carefully.
A. So long as B. In order that
C. No matter how D. The moment
20. Write to me as soon as you ________ to Beijing.
A. will get B. get C. getting D. got