引导时间状语从句的连接词有: when, as, while, after, before, since, ever since, as soon as, once, till, until, whenever, no sooner…than, hardly/scarcely…when, the moment/minute/instant/second, every time, each time, any time, the first time, next time, last time, all the time, by the time, directly, immediately, instantly等。
(1) as soon as/once As soon as he arrives, I’ll call you.他一到，我就给你打电话。（as soon as 侧重时间或动作先后衔接紧，而once侧重条件，表示“一旦…”）
(2) on doing sth/on one’s + n.作时间状语
On arriving at the station, the thief was arrested. 一到达车站，这个小偷就被逮捕了。
On his arrival in Paris, he was recognized as a noble and thrown into prison.
(3) no sooner …than , hardly/scarcely…when
No sooner had he reached home than it began to rain. 他刚到家，天就开始下雨了。 Hardly/Scarcely had I entered the room when the phone rang. 我一进屋，电话就响了。
当no sooner, hardly, scarcely不放在句首时，主句不倒装。
I had no sooner reached the bus stop than the bus started. 我刚到车站，车就开走了。
I had scarcely（hardly）entered the room when the phone rang. 我刚进房间，电话响了。
(4）the moment, the instant, the minute, the second
The moment I saw him, I recognized him. 我一看见他，就认出了他。
We’ll leave the minute you are ready. 你一准备好，我们就出发。
(5)有些副词如：instantly, immediately, directly可用作连词，后接从句。
I left immediately the clock struck 5. 我刚走，钟就敲了五点。
2）when, while, as引导时间状语从句
I was thin when I was a child. 当我是个孩子的时候,我很瘦。
It was raining when I arrived.我到达时，天正在下雨。
When (you are) in trouble, you can visit this man. 当你有麻烦时，可以找这个人。
She is always listening to music when（she is) doing her homework.
be about to do … when, be doing … when, had done ···when, be on one’s way … when, be on the point of doing … when
(2）while用法 while只能指一段时间，从句中的动词必须是延续性动词。强调某一段时间内发生主句动作，相当于during the time that….
My mother was cooking while I was doing my homework. 当我在做作业时，妈妈在做饭。
I am safe while I am here.我在这儿的时候，我很安全。
I like watching TV, while he likes reading. 我喜欢看电视，而他喜欢读书。
While he has his own car, he often uses mine. 尽管他自己有车，他却常用我的。
As I left the house, I forgot the key.我离家时，忘了带钥匙。
As I get older, I get more optimistic. 随着年龄的增长，我变得更加乐观。
He hurried home, looking behind as he went. 他匆忙地回家，边走边往后看。
As he was going out, it began to rain. 当他出去的时候，天开始下雨了。
As a boy (when he was a boy), he was hopeless at maths. 当他是孩子时，他对数学失去希望。
Before they got to the bus stop, the bus had gone.
②在“It be + 时间段 + before从句”句型中，肯定句译成“„（之后）才”，否定句译成“„就”。该句型有一般过去时、过去将来时、一般将来时三个时态，且有否定句。
It will be some time before… do…
It was some time before…did…
It would be some time before…did…
It was long before…did…“很久才···”
It wasn’t long before…did…“不久就…”
It will be many years before the chemicals start to escape from the containers.
It was not long before he came back.不久他就回来了。
It was a long time before he got to sleep again. 很久他才再次入睡。
It was a week before he could tell his story. 一个星期后他才能讲述他的经历。
It wasn’t long before he told us about himself. 不久他就给我们讲述了他自己的故事。
He had measured me before I could get a word. 我还未来得及插话，他就量好了尺寸。
▲before可译成“趁着还没” I’ll write it down before I forget. 趁着还没忘我要把它写下来。
I waited for him until he came back. 我一直等到他回来。
He didn’t go to bed until he had finished his work. 直到完成工作他才睡觉。
(3)用于强调句式“It is not until …that …”
It was not until the professor came that we began the experiment.
(4) not until放在句首时，主句倒装。
Not until he graduated did he succeed in obtaining this compound.
Mr. Li has been here since he came back. 自从李先生回来以后，他一直在这儿。
I haven’t heard from him since he lived here. 自从他住在这儿以来，我就没有收到过他的来信。 I’ve known Mr. Smith since I was a boy. 我小的时候就认识史密斯先生了。
Once (it is) seen, it can never be forgotten. 一旦被看见过，永远也不会被忘记。
1）地点状语从句主要由where, wherever anywhere, everywhere引导。
We must camp where we can get water. 我们必须在能找到水的地方露营。
I will follow you wherever you go. 无论你到何处我都要跟随你。
Go back where you came from.（where引导地点状语从句）
Go back to the village where you came from. （where引导定语从句，village为先行词）
原因状语从句由because, as , since, now (that)（既然）, in that（因为，多于口语中）,seeing (that)（鉴于，由于）,considering that（考虑到）等引导。
He didn’t attend the meeting because he was ill. 他没参加会议，因为他病了。
It was because he was ill that he didn’t go with us. 因为他有病，他没有和我们一起去。
because和because of的区别：because是连词，引导从句，because of是短语介词，后接名词性词语。
The football match was put off because it rained.
The football match was put off because of the rain. 因为下雨，足球赛延期了。
2）since, as, now that引导的原因状语从句，不能用于强调句。
Since you have known the secret, I needn’t say anything about it.
As he didn’t know much English, he got out his dictionary and looked up the word “cough”.
As the ground is wet, it must have rained last night.（倒果为因）
③ now that用来说明一种新情况，然后加以推论。now that放句首时that可省略。
Now (that) everybody is here, let’s begin.
He must be ill, for he is absent today.
As he was blind, he couldn’t see anything.
Being blind, he couldn’t see anything.
1）由if, unless（if…not）, so/as long as, supposing(that)（假设）, in case（万一…, 以防…）, so/as far as（就…而言）, on condition that（条件是…）, provided/providing (that)（假若）引导。
Tell me about it if you have time.
I won’t go unless I’m invited.
Take an umbrella with you in case it rains.
You may use the room as/so long as you clean it up afterwards.
Use your head, and you’ll find a way.
Hurry up or else (otherwise) you’ll be late.
3）if only也可以引导条件状语从句,只不过较少使用而已。only if也引导条件状语从句，意思是“只有在…条件下”
If (only) it clears up, I will go.
I will go if you go.
Come tomorrow if (it is) possible.
If so, you must get back and get it.
还有诸如if necessary“如果有必要”，if any“如果有”，if in need“若需要”。
If (water is) heated, water sends out steam.
Had I arrived there earlier, I would have seen him.
Were it not for him, I would not have the chance to go home.
Should he be here tomorrow, I would give him a hand.
由so that（以便）， in order that（为了），for fear that（= in case）（以免），lest（以防）引导，谓语常含may, might, can, could, will, would等情态动词。
They set out early so that they might arrive at the station in good time.
I’ll speak slowly so that/in order that you can understand.
He wrote the name down for fear that（lest）he would forget.
当从句与主句主语一致时，可用to do, so as to do, in order to do结构换用。
He worked day and night in order that he could succeed.
He worked day and night in order to succeed.
1）常用的连词有so that，so … that, such…that, that（带古英语痕迹）。（结果状语从句中一般无情态动词）
He had overslept so that he was late for work.
My pen fell under my desk that I couldn’t see it.
①so + adj（adv) + that从句
The box is so heavy that I can’t carry it.
②so+adj +a/an+单名+ that从句＝such a/an+adj.+单名+that从句
She is so beautiful a girl that all the boys of our class like her.
=She is such a beautiful girl that all the boys of our class like her.
③so many/few +复名+ that从句
so much/little+不可数名词+ that从句
There are so many apples on the desk that we each have one.
There is so little water that you can’t drink.
④such +a/an + adj + 单名+ that从句
She is such a good girl that she can help you.
⑤such + adj +复名/不可数名+ that从句
It was such bad weather that we all stayed home.
He has such interesting books that he keeps reading all day.
He is such a little boy that his patents often teach him something.
由as, as if (as though)引导。
Do as you like.
He spoke as if he had been there before.
as if, as though从句与事实相反时用虚拟语气，与事实相符，不用虚拟语气。
①常用连词than, as …as…, not as/so… as
He ran as far as he could.
I’m not as/so tall as he/him.
She studies harder than I（study）．
②the more … the more…引导, 且经常以省略形式出现
The harder you try, the better you will understand.
由though, although, as, even if/though , no matter wh-, wh-ever词，whether…or（不管…都），when, while等引导。
Although the TV set is very dear, I still want to buy it.
Though /Although he was worn out, he kept on working.
①形容词/副词/名词+ as +主 +谓
②动词+ as +主 +情态动词
Child as he is, he knows a lot.
Proud as these nobles are, they are afraid to see me.
Great a scientist as he is, he remains modest.
Try as I might, I couldn’t lift the stone.
Bravely though the players fought, they had no chance of winning.
3）even if（尽管；即使）, even though（尽管）
We’ll make trip even if(though) the weather is bad.
Even if I were in your place, I wouldn’t take the job.（虚拟）
Whether you believe it or not, it is true.
5）“no matter + wh-”引导让步状语从句
引导让步状语从句时“疑问句-ever”相当于“no matter +疑问词”，此时：
no matter who = whoever
no matter what = whatever
no matter which = whichever
no matter where = wherever
no matter how = however
No matter what happened, he would not mind.
It’s a nice room no matter whom (whoever) it belongs to.
6）“no matter + wh-”结构只能引导让步状语从句，而“wh-ever”形式除引导让步状语从句外，还可以引导名词性从句。
whoever = anyone who任何…的人…
whatever = anything that任何…的事（物）
whenever = anyplace where任何…的地方
I will give the book to whoever needs it.
I like whatever you like.
He walks when he might take a taxi.
when从句用虚拟式为：could/should … have done
She stopped trying when she might succeed next time.
No matter what he is, he will be punished.
Don’t speak until (you are) spoken to.
While (I was) in Beijing, I lived with my uncle.
I want to go swimming when (it is) possible.
Come tomorrow if (it is) possible.
If (it is) so, you would be punished.
Unless (it is) repaired, the TV set is of no use.
She stood at the gate as if (she was) waiting for someone.
Though (it was) cold, he still wore a shirt.
Fill in the blanks with proper words where (it is) necessary.