引导时间状语从句的连词有：when, as, while, until, not…until, before, after, since, the minute, the moment, each( every, next, the first) time等。时间状语从句中一般用一般现在时或一般过去时。
1．when , while, as都可解释为“当```的时候”但侧重点有所不同。
1) When后既可以接短暂性动词，也可以接延续性动词 ，表示从句动作与主句动作同时发生。
When I arrived home , I had a little rest.
He sang as he danced.(一面```一面) You will grow wiser as you grow older.(随着)
While we were working, they were having a rest.
While (they were) having a discussion, they got very confused.
注意：while 有对比的含义，解释为“然而”。eg: I prefer black tee, while he likes coffee.
肯定句：I waited until midnight. 否定句：I did not leave until midnight.
注意点：1）not until…在句首，主句用倒装 Not until you had explained how did I manage to do it.
2) It is not until…that…引导的强调句 It was not until it was dark that he came back.
3．Hardly/scarcely…when, no sooner…than, as soon as表示为“一```就```”
I had hardly/scarcely got home when it began to rain.
I had no sooner got home than it began to rain. It began to rain as soon as I got home.
条件状语从句分为两大类：真实条件句（主将从现）和虚拟条件句（虚拟语气）。引导条件状语从句的连词有：if, even if/though, unless/ if …not, as long as/ so long as, as far as/so far as, provided/providing (that), on condition that 等。条件状语从句中如果主句是将来时，条件状语从句用一般现在时。
1.unless 和if…not unless 相当于if…not
You will fail unless you study hard.
You will not fail if you study hard.
If she were not too silly,she would understand.
You may go there ,as long as you keep quite.
I will go provided that you go too.
I shall give you the book on condition that you return it tomorrow.
引导让步状语从句的连词有：though, although, even if/ though, however, no matter how, no matter what, no matter who等。
1．though, although不可与but连用，但可以和yet , still连用.
Though/Although it is raining ,they are still running outside.
2. “no matter+疑问词”或“疑问词+后缀ever”
No matter what happened, he would not mind.
Whatever happened, he would not mind.
3.even if/ though表示“即使”
He doesn’t want to marry her even if/ though he loves her very much.
引导原因状语从句的连词有：because, since, as , now that ,considering that, for the reason that , due to the fact that,owing to the fact that等。
1．because because语气最强，通常用于回答why 提出的问题
注意点：在it was…that…的强调结构中，强调原因状语从句可用because引导，不用since,as, for引导。
It is because she is too inexperienced that she does not know how to deal with the situation.
As/ Since you are not very well, you had better have a rest.
引导目的状语从句的连词有：so that, in order that, lest, in case, for fear that等。
You must speak louder so that/in order that you can be heard by all.
引导结果状语从句的连词有：so that, so…that, such…that等
He is so young that he can not go to school. He is such a young boy that he can not go to school.
such +a/an+形容词+单数可数名词+that从句 such +形容词+复数可数名词/不可数名词+that从句
such修饰名词或名词词组，so修饰形容词或副词,so还可接many, few, much, little等。
引导比较状语从句的连词有：as…as, not so…as, than, the more…the more等。
如：He speaks English as fluently as his brother (does)
I can’t jump so /as high as he (does)
There are more workers in this factory than in the one next to it .
The more you read, the more interesting , you will find the novel is .
引导地点状语从句的连词有:where, wherever以及 where构成的复合词等。
She found her calculator where she lost it. Wherever I am, I will miss you.
注意点：eg: I happened to see your dictionary lie where I used it last time.（地点状语从句）
I happened to see your dictionary lie in the lab where I used it last time.（定语从句）
引导方式状语从句的连接词有as, just as, as if / though（一般用虚拟语气， 也有用直陈语气的）等。
Just do as you are told.
The workers went on working as if nothing had happened.
He talked to the girl as though he had fallen in love with her.
在just as ---, so --- 结构中， as 带有比喻含义。意为“正如”， 多用于正式文体。
Just as some people like sports, so some people like music.
（ ）1.We'd better hurry ______ it is getting dark.
A.and B. but C. as D. unless
（ ）2. I didn' t manage to do it _____ you had explained how.
A. until B. unless C. when D. before
（ ）3._____ he comes, we won't be able to go.
A. Without B. Unless C. Except D. Even
（ ）4. I hurried _____ I wouldn't be late for class.
A. since B. so that C. as if D. unless
（ ）5. _____ I catch a cold, I have pain in my back.
A. Every time B. Though C. Even D. Where
（ ）6. What's the matter _____ they still haven't answered the telegram?
A. when B. that C. though D. however
（ ）7. Bring it nearer _____ I may see it better.
A. although B. even though C. so that D. since
（ ）8. You may arrive in Beijing early _____ you mind taking the night train.
A. that B. though C. unless D. if
（ ）9. Helen listened carefully _____ she might discover exactly what she needed.
A. in that B. in order that C. in case D. even though
（ ）10. More people will eat out in restaurants _____ they do today.
A. than B. when C. while D. as
（ ）11._____ hard she tries, she can hardly avoid making mistakes in her homework.
A. Much B. However C. As D. Although
（ ）12. Poor _____ it may be, there is no place like home, _____ you may go.
A. as; wherever B. though; whenever C. in spite of; when D. that; wherever
（ ）13. The child was __ immediately after supper.
A. enough tired to go to bed B. too tired to go to bed
C. so tired that he went to bed D. very tired, he went to bed
（ ）14. The history of nursing __ the history of man.
A. as old as B. is old than C. that is as old as D. is as old as
（ ）15. _____ born in Chicago, the author was famous for his stories about New York.
A. Since B. Once C. When D. Although
（ ）16._____ we stood at the top of the building, the people below were hardly visible.
A. As B. Although C. Unless D. In spite of
（ ）17. Scarcely was George Washington in his teens _____ his father died.
A. than B. as C. while D. when
（ ）18. _____ David goes, he is welcome.
A. Whichever B. However C. Wherever D. Whatever
（ ）19. The house stood _____ there had been a rock.
A. which B. at which C. when D. where
（ ）20. Small _____ it is, the pen is a most useful tool.
A. because B. so C. if D. as
（ ）21. After the new technique was introduced, the factory produced cars in 1988 as the year before.
A. as twice many B. as many twice C. twice as many D. twice many as
（ ）22. The piano in the other shop will be _____, but _____.
A. cheaper; not as better B. more cheap; not as better
C. cheaper; not as good D. more cheap; not as good
（ ）23. John plays football _____, if not better than, David.
A. as well B. as well as C. so well D. so well as
（ ）24. Although he is considered a great writer,
A. his works are not widely read B. but his works are not widely read
C. however his works are not widely read D. still his works are not widely read
（ ）25. ___ the day went on, the weather got worse.
A. With B. Since C. While D. As
（ ）26.—What was the party like? —Wonderful. It' s years _____ I enjoyed myself so much.
A. after B. when C. before D. since
（ ）27. It was not _____ she took off her dark glasses _____ I realized she was a famous film star.
A. when; that B. until; that C. until; when D. when; then
（ ）28. If we work with a strong will, we can overcome any difficulty, _____ great it is.
A. what B. how C. however D. whatever
（ ）29. After the war, a new school building was put up _____ there had once been a theatre.
A. that B. where C. which D. when
（ ）30._____, Mother will wait for him to have dinner together.
A. However late is he B. However he is late
C. However is he late D. However late he is