初中英语语法连词词专项习题[ Because, since, as, for ]because, as, for, since这几个词都是表示“原因”的连词，语气由强至弱依次为：because→since→as→for;其中because, since, as均为从属连词，引导原因状语从句；而for 是并列连词，引导并列句。
1. because表示直接原因，它所指的原因通常是听话人所不知道的，其语气最强。
常用来回答why的提问，一般放于主句之后，也可以单独存在。
例如：(1)I stayed at home because it rained. 因为下雨我呆在家里。
(2)Because Lingling was ill, she didn't come to school. 玲玲因病，没有上学。
(3)—Why is she absent? 她为什么缺席？—Because she is sick. 因为她病了。
此外，在强调句型中，只能用because。
例如：(4)It was because I missed the early bus that I was late f or school. 我上学迟到是因为我没有赶上早班汽车。
2. since侧重主句，从句表示显然的或已为人所知的理由，常译为“因为”、“既然”，语气比because稍弱，通常置于句首，表示一种含有勉强语气的原因。
例如：(1)Since he asks you, you'll tell him why. 他既然问你，那就告诉他为什么吧。
(2)Since everyone is here, let's start. 既然大家都到齐了，我们就出发吧！(3)Since I understood very little Japanese, I couldn't follow the conversation. 我日语懂得不多，因而听不懂对话。
3. as是常用词，它表示的“原因”是双方已知的事实或显而易见的原因，或者理由不是很重要，含义与since相同，但语气更弱，没有since正式，常译为“由于，鉴于”。
从句说明原因，主句说明结果，主从并重。
例如：(1)We all like her as she is kind. 我们都喜欢她，因为她善良。
(2)As I had a cold, I was absent from school. 因为我感冒了，所以没去上课。
(3)As Xiaowang was not ready, we went without him. 由于小王没有准备好，我们只好不带他去了。
4. for用作连词时，与because相似，但它所表示的原因往往提供上文未交待过的情况。
for不表示直接原因，表明附加或推断的理由，因此for被看作等立连词，它所引导的分句只能放在句子后部(或单独成为一个句子)，并且前后两个分句间的逻辑关系不一定是因果关系，其间用逗号隔开，且for不可置于句首，for的这一用法常用在书面语中，较正式。
例如：(1)The days are short, for it is now December. 白天短了，因为现在已是十二月份。
(2)It must have rained, for the ground is wet. (从“地面潮湿”作出“下过雨”的推测，但地湿并不一定是下雨所致, for不可以换为because。
)(3)The ground is wet because it has rained. (“下雨”是“地上潮湿”的直接原因。
) 前后两个分句间有一定的因果关系时(有时很难区分是直接原因，还是推测性原因)，for与because可以互换使用。
例如：(4)I could not go, for / because I was ill. 我没能去，是因为我病了。
(5)He felt no fear, for / because he was a brave boy. 他没有害怕，因为他是个勇敢的男孩。
Because/asbecause 引导的是必然原因，as引导一般原因。
必然原因是指某事发生必会导致另一件事实。
一般原因语气还有其因果关系不是很明显。
以下两个句子请体会The floor is wet,because it rained this morning.As the floor is wet, it might rain this morning.(地板湿也可能是其他原因，以此看，as引导原因从句还有猜测的意味。
)Because/for这两个词的意思很相近，通常是可以互换使用的。
为了安全起见，最好用because引导从句，因为同because引导的从句相比，for引导的从句（英文中称为for－clause）的用法要受到某些限制：1 for引导的从句不能位于它所解释的动词之前：Because it was wet he took a taxi．因为下雨，他叫了一辆出租车。
（这里不能用for。
）2 for引导的从句不能位于not，but或任何连词之后：He stole，not because he wanted the money but because he liked stealing．他偷东西，并不是因为他想要钱，而是他有这种毛病。
（这里不能用for。
） 3 for 引导的从句不能用于回答问题：—Why did you do it？—I did it because I was angry．—你为什么这么做？—因为我生气才这么做的。
（这里不能用for。
）4 for引导的从句不能单单用来复述已讲过的话，而必须包括新的容：He spoke in French．She was angry because he had spoken in French．他讲法语。
因为他讲法语，她生气了。
（这里不能用for。
）但是可以说：She was angry，for she didn’t know French．她生气了，因为她不懂法语。
（这里用for是正确的，也可用because。
）之所以有这些用法上的限定，其理由是for引导的从句不能直接说明某一特定动作发生的原因，而只能提供一些起帮助解释作用的附加说明。
例句如：The days were short，for it was now December．天短了，现在已是12月了。
He took the food eagerly，for he has eaten nothing since dawn．他狼吞虎咽地吃了起来，因为他从天亮就没吃过东西。
1. He can speak English_______ Chinese.A. butB. alsoC. soD. and2. Physics is not so easy, _______I like it very much.A. butB. orC. sinceD. because3. Will Tom wait for her at home ______ at the library?A. orB. asC. so thatD. both4. She has a son _______ a daughter.A. butB. andC. soD. or5. I'll give her the gift ______ she arrives.A. soB. beforeC. as soon asD. since6. Tom was ____ill that we had to send for a doctor.A. soB. veryC. andD. too7. The woman was____ angry_____ she couldn't speak anything.A. neither…norB. either…orC. both…andD. so…that8. ______we got home it was very late.A. WhenB. WhileC. BecauseD. As9. We heard clearly_____ she said.A. whatB. whichC. beforeD. because10. I can't sleep well at night, ______I often feel very tired in the day.A. soB. becauseC. andD. or11. When you're learning a foreign language, use it, ______ you will lose it.A. butB. orC. thenD. and12. --- Can you play football?--- Yes, I can, ______ I can't play it very well.A. orB. andC. butD. so13. Study hard, ______ you will fall behind.A. andB. butC. soD. or14. My favorite is action movie ______ I think it's exciting.A. andB. becauseC. butD. so15. The boy is very smart, ______ many of his classmates like him.A. butB. soC. orD. for16. He has never heard______ seen such a thing before.A. norB. andC. orD. since17. _________ John _______I are policemen.A. Neither ... norB. Either ... orC. Both ... andD. Not only... but also18. Mr Smith teaches ______well ______ his lessons are not easily forgotten.A. very ... thatB. quite ... butC. so ... asD. so ... that19. He didn't go to sleep ______he finished his homework.A. tillB. beforeC. afterD. until20. I didn't buy the dictionary yesterday ________ my aunt would give me one.A. untilB. becauseC. ifD. before21. The runner fell _______ he quickly got up and went on running.A. orB. andC. butD. down22. Wait for me in the room _______ I come back.A. untilB. andC. soD. or23. I'll return the books to the library ______ soon as possible.A. asB. soC. justD. but24. Go along the road, _______ you'll find the market at the end of it.A. whenB. andC. orD. though25. You'll be late ______ you don't get up early tomorrow morning.A. ifB. whenC. beforeD. until26. It was late. She washed her face ______ went to bed.A. orB. andC. soD. but27.He shouted aloud ______he ran alone.A. afterB. beforeC. when D .as28.Please return the book to me _____you come back.A. as soon asB. whenC. whileD. as29..Ring me up____ you come to my house.A. though B as C. before D .then.30. I must stop writing now ,______I have rather a lot of work to do.A .aB .so C. when D. since31.The bus didn’t leave _____ everyone get on .A .afterB .whileC .until D. when32.I’ll leave a message _____ he will know whe re we are .A .so that B. as soon as C. for D. that33. My sister is ____young ____he can’t go to school .A, too , to B. enough; to C. so that D. as ;as34. His brother got up earlier ____ he could catch the bus .A. as if B .so C . so that D .than35 .It is almost three years ____I saw he last .A .when B. since C. after D. that36.---I’m going to the supermarket .----Will you get me some chocolates ____you are here ,mum .A .sinceB becauseC ifD . while37 .Mr Green came to China in 2000,______he has lived here ever since.A . and B. or C .but D. for38 .____ they are brothers , they don’t look like each other at all.A, Because B .Though C. When D, As39 .I know nothing about it ____ my brother told me yesterday.A .because B. since C. until d. so40. He failed _____ because he isn’t clever ______ because he didn’t work hard.A. not only …..but alsoB.both ….andC. either …orD. not …but41.The teacher wondered why he had ____questions.A. so much B .so many C such much D . such many42. We were swimming in the lake ____suddenly the storm started .A. whenB. while C until D . before43. We can_____ see ____touch the air .A .not only ,but alsoB .both, andC . either ,orD . neither ,nor44. You can____ stay at home _____ go to my hometown with me .A. not ,onlyB. either and C .both or D. either or45. We left in _____a hurry _____we forgot to lock the door .A. so , soB. so ,that C . such ,that D . such so46. __Judy, you look so tired.__Yes. I did not go to bed ____ it was twelve last night.A . when B. unless C. until D. after47. She was so interested in the book that she has read it for three hours ____ she realized it.A. untilB. beforeC. after D .when48. Jack spend much money on books ____ he is so rich.A. thoughB. whenC. ifD. because49John feel asleep ____ he was listening to the music.A. afterB. beforeC. whileD. as soon as50. She does not feel like playing basketball now, ____, she is not good at it.A. soB. orC. butD. besides51. Mother is ill,_____ Father cooked for us instead.A. butB. orC. soD.and52.----It’s 9 o’clock now .I must go .-----It’s raining outside .Don’t leave _____it stops.A. whenB. sinceC. while D .until53.Would you like to go to the concert with me?-----I’d love to ______ I can’t .A. orB. butC. soD. and54. ---Our holiday cost a lot of money .----Did it ?Well ,that doesn’t matter ____you enjoyed yourselves.A. if B unless C while D. or55.He didn’t come to school yesterday ,____he was ill.A. ifB. becauseC. whenD. before56.----Can you guess who will be the first to cross the finish line ?---Sandy. Jane didn’t run so fast _____ she did last time.A. thanB. so C .that D as57 Nothing can stop the sandstorm ____ more and more trees are planted.A. unlessB. ifC. whenD. while58. I have to finish the work now ____ I will fall behind others.A. andB. orC. butD. so59. D o you prefer apples ____ grapes?A. toB. thanC. or60. I met Miss Green ____ I was walking across the bridge, but I did not say hello to him.A. beforeB. afterC. untilD. while61. I can not afford to buy a CD player ____ it is too expensive.A. afterB. thoughC. becauseD.until62. I would like to play football with you ____ I have got a meeting now.A. andB. orC. butD. so63. Edison never give up, ____ he failed many times.A. andB. thoughC. orD. so64. You should make a plan ____ you do anything important.A. beforeB. afterC. thoughD. until65. Forests help to keep water from running away, ____ drought does not often happen.A. andB. butC. soD. though66. We all like Han Mei ____ she is kind and helpful.A. soB. andC. becauseD. but67. We will not never give up our plan ____ happens.A. howeverB. whateverC. wheneverD. wherever68. The box is so heavy ____ I have to ask someone to help me.A. toB. becauseC. thatD. for69. It was so late, ____ the farmers went on working in the field.A. andB. orC. soD. but70. The little boy is only six years old, ____ he can make model wonderful cars.A. butB. soC. orD. and71. Shirley has passed the exam ____ she is busy with her hard work.A. becauseB. whenC. sinceD. though72. Linda was just going out shopping ____ the telephong rang.A. whileB. whenC. afterD. because73. I want to know ____ Jack still lives in that house.A. thatB. ifC. weatherD. where74. I bought a present for my friend, ____ she did not like it at all.A. andB. butC. soD. or75.They did not start the work ____ their teacher came back.A. untilB. whileC. as soon asD. if76. Hurry up! ____ you will be late for the film.A. AndB. ButC. OrD. Because77. When you are learning English, use it, ____ you or lose it.A. butB. orC. thenD. and78. The doctors tried their best to save the patient’s life ____ failed.A. orB. soC. butD. because79. Study hard _____ you are sure to have a good result.A. orB. andC. forD. but80. Sam was reading a newspaper ____ his brother fell on the ground.A. whenB. whetherC. as soon as81. I tried to call you ____ I heard from him, but you were not in.A. sinceB. whileC. untilD. as soon as82. Jack is only four years old, ____ he can draw beautiful pictures.A. butB. soC. orD. since83. I hardly know anything about it ____ you told me.A. sinceB. afterC. untilD. when84. I have not see her ____ she left Lanzhou.A. whileB. whenC. sinceD. from85. WeiHua always helps others ____ she is very busy.A. thoughB. ifC. because86. None of us knew what had happened ____ we heard the news.A. afterB. untilC. when87. I left my umbrella in my room. Could you wait ____ I go back to get it.A. whenB. ifC. whileD. before88. He is so tired that he fell asleep ____ he went to bed.A. as ifB. even thoughC. ever sinceD. as soon as89. Come a little earlier next, ____ you will miss the best the part.A. andB. butC. orD. till90. The Yellow River is ____ the Changjiang River.A. not so long asB. as long asC. not long asD. longer than91. There goes the bell. Hurry up, ____ you will be late for class.A. andB. thatC. orD. but92. There is a lot of traffic in this city, ____ look both ways before crossing the street.A. soB. andC. butD. for93. Which one is yours, A ____ B？A. butB. andC. or94. Tom is ill at home, ____ he can not come here.A. soB. ifC. because95. All of us will be happy ____ you can come with us.A. whileB. ifC. butD. or96. He is only five years old, ____ he can write novels.A. soB. butC. or97. Tomorrow we will go to the city park ____ it is sunny.A. as soon asB. whenC. ifD. as98. If you can not get to sleep, then get up and try to do something ____ lying in bed.A. andB. orC. instead ofD. because of99. I did not finish my home work, ____ my teacher was angry with me.A. soB. \C. or100. The sports meeting will continue ____ it rainy this afternoon.A. ifB. sinceC. as soon asD. until答案：1-5 DAABC 6-10 ADAAA 11—15 BCDBB16-20 CADDB21-26 CAABAB 27-30 DACAC 31-36 ACCBA 37-40 DCBCD 41-45 BADDC 46-50 CBACD 51-55 CDBAB 56-60 DABAD 61-65 CCBAC 66-70 CBCDA 71-75 AABBA 76-80 CBCBA 81-85 DBDCA 86-90 BDDCA 91-95 CACAB 96-100BCCAD如果觉得文档还不错，请用手机taobao扫描下方二维码（左）收藏一下；更多中学英语资料，请加wx（右）。