分析语境 辨明原因
用来说明原因的方法有许多：用连词引导原因状语从句；用介词（结构）引导表原因的短语或从句；用分词短语作原因状语，用With 结构表原因。但是语境不同引导词也应不同，并且表达方式也有相应的变化。
一、用连词引导原因状语从句
1. because 因为：用来回答 Why 的提问或表达直接的理由
You only do it because you have to .你没有选择，只有这样做。
He distrusted me because I was new . 我是新手，他不信任我。
这类从句放在句尾较多，为了强调原因也可置于句首：
Just because they make more money than I do ,they think they're so superior.仅因为挣的钱比我多，他们就认为自己很优越。
2. for 因为：多用于书面语，一般和前面部分用逗号分开，引起的从句对主句加以解释
Don't swear , for I dislike swearing. 你不用发誓，我讨厌发誓。
We must start early , for we have a long way to go .因为有远路要走，我们得早点出发。
有时它引导的从句并不表示原因，而是对前面的情况进行推测：
I t must have rained in the night , for when I woke the next morning I saw the grass wet .早上醒来我发现草湿漉漉的，晚上一定下过雨。
3. as 由于，因为
We don't go there much now ,as we're going away so soon .因为我们很快就要走了，所以现在不常去那儿。
As all the seats were full he stood up . 座位坐满了，他只好站起来。
偶面明"既然"之意：
As you sow ,you shall reap . 种瓜得瓜，种豆得豆。
4. since 既然：用来表达众所周知的理由
Since we've no money , we can't buy it . 既然没钱，我们就不能买。
Since you are going , I will go too . 你要走，我也要走了。
5. now (that ) 既然
Now (that) we have gone so far , we might go a little further .我们已经走了这么远，还可以再走得远一些。
Now (that) you are well again , you can travel .你已康复，可以远行了。
6. seeing (that) 鉴于
Seeing that he is ill , we'll do that work for him . 他病了，咱们会为他把事办好的。
Seeing (that) he refused to help us , there's no reason why we should now help him.他拒绝帮助我们，我们现在也就没有什么理由帮助他了。
7. that 因为，由于：引导状语从句，表明原因和理由
It is rather that he was ill then . 更主要的是他当时病了.
We are glad (that) we have reaped another bumper harvest . 我们很高兴又是一个大丰收。
8. being as (或 that ) 既然，因为：多用于口语中
Being as we're all here , let's start . 既然都来了，咱们就开始吧。
Being that he gives it up , there is no need to wait for him . 既然他已放弃，就没必要等他了。
9. the rather that 因为……所以更加
I'll not go now , the rather that it's too late . 因为很迟了，所以我现在更不会走了。
He doesn't believe you ,the rather that you are still lying now . 他不会相信你，更何况你现在还在撒谎。
10. when 既然，考虑到
Why use metal when you can use plastic? 既然能用塑料，为什么还使用金属？
How could you, when you know that this might damage the apparatus ? 你知道这样会损坏仪器，你怎么还这样做？
11. in that 既然，因为
Criticism and self-criticism is necessary in that is helps us to correct our mistakes .
批评和自我批评是必要的，因为它能帮助我们改正错误。
I like the city ,but I like the country better in that I have more friends in the country .
我喜欢城市，但我更喜欢乡村，因为乡下我的朋友更多。
二、用介词（结构）引导表原因的短语或从句
1. because of 因为
I've chosen them because of the colors .我选中它们是因为它们的颜色。
He realized that she was crying because of what he had said . 他意识到因为他说过这些话，她才哭。
2. at 为，由于……引起某种情绪的原因
We all rejoiced at the news of your success .你成功的消息使我们感到高兴。
He showed no sign of pleasure at seeing her .看到她时，他并无一丝兴奋。
3. in consideration of 考虑到，由于
He received five dollars in consideration of his age . 考虑到他的年龄，他收下了5元钱。
John got some money in consideration of his services . 因为他的服务，赚到了一些钱。
4. on behalf of 因为……缘故
He worked hard all his life on behalf of the poor.他一生为穷人努力工作。
Don't trouble to do is on my behalf .不要为了我去麻烦了。
5. to 由于
The boxer fell to his opponent's blows . 拳击手倒在对手的拳头下。
A wolf fell to the hunter's rifle . 一只狼倒在猎人的枪口下。
6. through 由于
Sometimes we make mistakes just through carelessness . 有时我们因为粗心而犯错。
That was done through friendship . 那样做完全是出于友情。
7. thanks to 幸亏 ，由于
We were ready in time ,thanks to you . 多亏你，我们才及时准备好。
Thanks to their youth and upbringing ,they were not upset by the accident . 幸亏他们年轻和幼年的教育，才没使他们对事故感到十分不安。
8. owing to 由于
Owing to our joint efforts , the task was fulfilled ahead of time . 由于大家的共同努力，任务提前完成。
She is now , owing to ill health , not so active in the movement . 如今她的身体不好，在活动中不太活跃。
9. due to 由于
The flight was cancelled to the fog 。 由于大雾，航班取消。
The accident was due to his careless use of the gun . 枪支走火引起事故发生。
10. on account of
That was on account of the lack of exercises . 那是由于缺乏锻炼引起的。
At first he hesitated on account of the expense . 他起初是因开支的问题在犹豫。
11. out of 出于，由于
I have done that out of regard for my sister . 我这样做是出于对我妹妹的关心。
We did this just out of concern for our comrades . 出于对同志的关心我们才这样做。
12. from 出于，由于
From no fault of their own ,they lost all their money . 并非他们自己的过错，赔掉了老本。
We were all weak from hunger, not having had food for over hours . 几个小时滴水未进，我们都饿得疲惫不堪。
13. What with 由于……种种原因
What with overwork and what with hunger ,John fell ill . 约翰病倒了，一半由于过度劳累一半由于饥饿。
What with the ice and snow , It's nicer to stay indoors . 冰天雪地的，最好呆在家里。
14. for the sake of 由于……的缘故
The men tolerated him for the sake of his good heart . 因为他的心肠好，大家都能容忍他。
He bought a house in the country for the sake of his wife's poor health . 由于他妻子身体不好，他在乡下买了一套房子。
15. after 由于 ，因为
After what has happened , he won't go . 既然发生了这一切，他就不去了。
After what had happened you couldn't continue to work here . 由于发生了这样的事，你不能继续在此工作了。
三、用分词短语作原因状语
1. 现在分词短语原因
Not knowing what to do next , he was much worried . 他焦急万分不知接着该做些什么。
= Because he didn't know what to do next , he was much worried .
2. 过去分词短语原因
Badly wounded in his left leg , the soldier walked unsteadily . 战士右腿受重伤，走路蹒跚。
= Because he was badly wounded in his leg , the soldier walked unsteadily .
3. 独立结构表原因
There being a little time left ,we have to be hurried . 时间所剩无几，我们只好赶忙。
= As there was a little time left ,we have to be hurried .
四、用with结构表原因
1. with + 名词
Hearing the good news ,the students all jumped with joy . 听到好消息，学生们欢呼雀跃起来。
2. with + sb. / sth .+ 现在分词短语
With the teacher standing by him ,the pupil felt very nervous . 因为老师站在旁边，这位小学生很紧张。
3. with +sb. / sth + 过去分词短语
With everything taken away from him , Einstein had to leave his homeland . 所有的一切都被剥夺了，爱因斯坦只好背井离乡。
4. with + sb ./ sth . + 形容词或副词短语
With the windows wide open ,they felt cold in the house . 窗户洞开，他们在房子里冷极了。
With the moon up in the sky ,we could see the road clearly . 皓月当空，我们能看清道路。
5. wih + sb ./ sth .+ 介词结构
With so much money about him ,the passenger couldn't sleep on the train . 由于有重金在身，乘客不敢在火车上打瞌睡。

1. Charles Darney insisted that he _____everything he could to make sure of Lucie's happiness.
　　　A. do B. does C. did D. must do
　2. How I wish that the disabled _____ good care of.
　　　A. will be taken B. would be taken C. must be taken D. be taken
　3. If Sydney Carton _____ Charles Darney , the latter _____.
　　　A. didn't help; would die B. hadn't helped ; might die
　　　C. hadn't helped ; would have died D. shouldn't help; should have died
　4. He has never travelled in any big cities, but he talks about London as if he _____ there.
　　　A. has been B. has gone C. had been D. had gone
　5. Without the sun, none of the living things on earth ________.
　　　A. existed B. would exist C. would have been existed D. exists
　6. _______ tomorrow, I might go with you.
　　　A. If you will go B. If you go C. If you would go D. Should you go
　7. Holmes made a demand that he as well as his assistant ______ in the lady's room that night.
　　　A. should lock B. be locked C. would be locked D. was locked
　8. You have failed again. I think you _____ harder.
　　　A. ought have studied B. ought to have studied C. must have studied D. may have studied
　9. You _______ in such a hurry. After all, the station was quite near the hotel.
　　　A. must have been B. should have been C. needn't have been D. might have been
　10. Had you taken the doctor's advice, you ______ all right now.
　　　A. are B. were C. would have been D. might be
　11. I don't think it is the right time that you ______.
　　　A. will go B. went C. go D. must go
　12. It is necessary that you ______ spoken English now and then.
　　　A. might practise B. practise C. should practise D. would practise
　13.His room looks very dirty as though it _______ for years.
　　　A. has not been cleaned B. were never cleaned
　　　C. had not been cleaned D. was not cleaned
　14. Martin Luther Kin, Jr. was famous all over the world, even though he _____ his Dream Speech.
　　　A. wouldn't make B. didn't make C. had made D. hadn't made
　15. On the boy's face, there was a sweet smile, which suggested that he _____ happy to give
　　　his life for his country.
　　　A. should be B. was C. had been D. would be
　16. Dr Monette wrote a letter, insisting that the two nobles _____ great wrong to the peasant boy and his
　　　sister.
　　　A. had done B. should do C. should have done D. did
　17. You _______ earlier. The bus left a moment ago.
　　　A. would have come B. should have come C. might have come D. must have come
　18. I _______ you some money, but I hadn't any on me then.
　　　A. would have lent B. would lend C. could lend D. should lend
　19. ______ that the old man give up smoking.
　　　A. It is requested B. It is hoped C. It is wished D. It is reported
　20. We started out early in order that we _________ in time.
　　　A. would get B. got C. must get D. wanted to get
　21. "I want an apple ", " ______ too ".
　　　A. I B. Me C. Mine D. Myself
　22. ______ to rain tomorrow , they would put off the meeting.
　　　A. If it should B. If were it C. Should it D. were it
　23. ______ got into the room ______ the telephone rang.
　　　A. No sooner had he, when B. He hardly had, then
　　　C. Hardly had he, when D. He hardly had , then
　24. ______ find out what had happened.
　　　A. Until he woke up did he B. Until he woke up to
　　　C. Not until did he wake up he D. Not until he woke up did he .
　25. Little ______ about his own health though he was very ill.
　　　A. he cared B. he cares C. does he care D. did he care
　26. Early in the day ______ the news ______ the enemy were gone.
　　　A. come , that B. came , that C. comes ,that D. came , what
　27. Not only ______ strict with us, but also ______ for us .
　　　A. was the teacher ; did he care B. was the teacher ; he cared
　　　C. the teacher was ; did he care D. the teacher was ; did he care
　28. ______ ,he knows a lot of English .
　　　A. Child as he is B. As he is a Child
　　　C. A child as he is D. Child though he was
　29. ______ the cat , she has to give it to the neighbour.
　　　A. As she likes much B. As she much likes
　　　C. Much as she likes D. As much she likes
　30. Be quick ! ______ .
　　　A. Here comes the bus B. The bus here comes
　　　C. The bus come here D. Here the bus comes
　31. If you want to go there , ______ .
　　　A. so will I B. so I will C. I will so D. so do I
　32. In front of the farmhouse ______ .
　　　A. does a small boy sit B. did a small boy sit
　　　C. sit a small boy D. sat a small boy
　33. Scarcely ______ down when ______ a knock at the door .
　　　A. had he sat ; did he hear B. he had sat ; did he hear
　　　C. he had sat ; he heard D. had he sat ; he heard
　34. Here ______ .
　　　A. does he come B. he comes C, comes he D. he come
　35. Only ______ that .
　　　A. can a doctor do B. a doctor can do
　　　C. can do a doctor D. can a doctor does
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