2021年初中英语语法：原因状语从句详细解说(附大量例句)

2021年初中英语语法：原因状语从句详细解说(附大量例句)
一、概述：
原因状语从句是指在复合句中表示主句动作发生原因的句子。

原因状语从句可置于句首，也可置于句尾。

引导原因状语从句的常用词可分为两类：单词引导词和短语引导词。

单词引导词主要有because、since、as等；短语引导词主要有now that、seeing that、for the reason that、in that、considering （that）等。

二、详细解说
1. because的用法
because引导的原因状语从句往往比主句显得更重要。

表示动作发生的直接原因,表因果关系的语气最强,用来回答why引导的疑问句,所引出的原因往往是听话人所不知道或最感兴趣的。

如:
1)Why didn't you go with us today?
你为什么今天没跟我们一起去?
一Because I was too tired.
因为我大累了。

2)He is leaving because he is fed up with the boss.
他离开是因为他厌烦老板。

3)I did not go to school yesterday because I was ill.
我昨天没去上学,因为我生病了。

4)Because it was raining, I had to stay at home.
因为下雨,我只好待在家里。

*注意：汉语里我们习惯说“因为……所以…”,但使用英语时不能将because与so连用。

表示因果关系时只能二选一。

如:
Because my bike was broken, so I went to school by bus yesterday. (误)
I went to school by bus yesterday because my bike was broken. (正)
My bike was broken, so I went to school by bus yesterday. (正)
因为我的自行车坏了，所以我昨天坐公共汽车上学。

Because my mother was ill, so I didn't go to your party(误)
I didn't go to your party because my mother was ill. (正)
My mother was ill, so I didn't go to your party. (正)
因为我妈妈病了,所以我没去参加你的聚会。

2. since 的用法
since意思是“既然,由于,因为”,表示已知的、显然的理由,较正式,多位于句首。

since引导的从句是次要的，重点强调主句的内容。

1)Since tomorrow is LI Hong's birthday, let’s give him party.
既然明天是李宏的生日,咱们给他开一个派对吧。

2)Since everyone is here, let’s start our class.
既然大家都来了,咱们就开始上课吧。

3)Since you are free, you'd better tidy your bedroom.
既然你有空,你最好把卧室整理一下。

4)Since it is late, I shall go home right now.
(由于)时间不早了,我得马上回家。

3. as的用法
as与since用法差不多,所引出的理由在说话人看来已经很明显,或已为听话人所熟悉而不需用because加以强调。

as引导的从句与主句同等重要。

1)As you were not there, I left a message.
因为你不在那里,所以我留了个信儿。

2)We have to delay our journey, as the weather is so bad.
天气太恶劣了，我们要推迟行程。

3)As rain has fallen, the air is cooler.
因为下过雨，空气比较清新。

4)As Monday is a national holiday, all government offices will be closed.
由于周一是法定假日，所有的政府机关都将休息。

4. because, since和as的用法区别：
和because相比, since和as的语气稍弱。

①because语气最强,用来回答why引起的提问,可表示已知或未知的事实。

它可和强调词only, merely, just及否定词not连用,所引导的从句常位于主句之后,只有强调时才置于主句之前。

它还可用于强调结构。

1) I did not go to school yesterday because I was ill.
我昨天没去上学,因为我生病了。

2) It was because I wanted to see my uncle that I went to town yesterday.
因为想去看叔叔我昨天才进城的。

3) He was punished only because he broke the law.
他就是因为触犯了法律才受到惩罚的
②since的语气也较弱。

常表示对方已知的事实,相当于汉语的“既然”。

之前不可用强调词和not,亦不可用于强调结构。

Since everyone makes mistakes, you shouldn't always criticize him.
既然每个人都会犯错误,你不应老是批评他。

③as语气最弱,较口语化。

所表达的原因比較明显或是已知的事实,故不需要强调。

之前不可用强调词和not,且不可用于强调結构。

as从向多置于主向之前。

As it was getting late, I turned around to start for home.
由于天色渐晚,我就调头回家了。

5. for的用法
并列连词for，放在主句之后，并通常以逗号将其引导的从句与主句分开，它不能直接说明原因，引导后半句对某种情况进行推测来作为补充说明的理由，语气较because, since, now that弱，但较as要强。

1)We listened carefully, for the speech was very important.
我们认真听讲因为这个演讲很重要。

2)The day gets long, for it is summer now.
白天变长因为现在是夏天了。

3)It rained last night, for the ground is wet this morning.昨晚下雨了，因为今天早上地都
湿了。

4)Tom must be ill, for he is not in the office today. 汤姆肯定病了，因为他今天不在办公
室。

相比较而言：
as和for引导的主、从句，二者处于平等位置；
because引导的从句显得比主句重要，强调原因；
since引导的从句显得次要，而主句重要，以说明将要做什么事。

6. now(that) (既然)的用法
now(that)主要用于口语,表示微弱的原因,主从句因果关系不明显,常译为“既然”。

1)I’m going to relax now (that ) the school year is over.
这一学年结東了、所以我打算放松ー一下。

2)Now (that) you have come, you may as well stay.
既然你已经来了,那就留下来吧。

3)Now that she understood, her anger faded away.
既然她明白了，她的怒气就消了。

4)Now that they've got to know each other a little better, they get along just fine.
由于彼此间有了进一步的了解，他们相处的不错。

5)Now that a tunnel has been built through the mountains，the pass is less dangerous. 由于
一条穿山隧道已经开通，翻越山口已不那么危险了。

6)He soon discovered how much faster he could travel now that he was alone. 由于是只身
一人，他很快便发现他可以比先前走得快得多。

7. in that（因为）的用法
用于说明为什么主句所表达的陈述是确实的
1)I'm in a difficult situation in that I have been offered two jobs and they both sound
interesting. 我之所以为难，是因为我有两份工作可选择，并且它们看上去都还不错。

2)He failed to arrive at the airport punctually in that he had suffered a terrible traffic jam.他
之所以没能准时到达机场是因为他遇到了严重的塞车。

3)I like the city, but I prefer the country in that there is fresher air.
我喜欢城市，但我更喜欢乡村，因为那里有更清新的空气。

8. seeing that（由于，鉴于）的用法
seeing (that), now that 和since, as 意义相似，他们都有“鉴于某个事实”的意思，that可以
省去
1)Seeing that I live further uptown than you, I could, theoretical, pick you up. 鉴于我住得
比你远，理论上，我可以捎带你一程。

2)Seeing that you're the guest on this little trip，I won't tell you what I think of your
behavior last night. 鉴于你是这次短途旅行的客人，我就不再评说你昨晚的行为了。

3)Seeing that he is inexperienced, he is not fit for the work.
既然他没有经验，他就不适合这项工作。

9. 其他连接引导词的原因状语从句
for the reason that, considering (that), not that...but that...等也可引导原因状语从句。

1)I often go to the cinema for the simple reason that I love seeing films. 我经常去电影院，
原因很简单，那就是因为我喜欢看电影。

2)Considering (that) he hasn't fully recovered yet, it will not be proper to assign him such a
hard job. 考虑到他身体还没有完全恢复，不适合指派他干这么难的工作。

3)They did the job quite well considering（that）they had no experience. 考虑到他们没有
任何的经验，这份工作他们算做得相当不错了。

4)It is not that I dislike the task but that I am unequal to it.不是因为我不喜欢这个任务，而
是由于我确实不堪此任。

10. 另外，在使用原因状语从句的时候还要注意以下几点：
第一，当because放在句末，且前面是用逗号分隔开的，那么它可以用for来替代。

第二，如果不是表直接原因，而是推测，那么就要选for.
第三，在because引导的原因状语从句里，当主句的主语与从句的主语一致，并且谓语动词是be时，一般省略从句的主句和谓语。

第四，当主句的主语与从句的主语一致时，可简化成分词短语作状语
【例】Since Tom did not know English. He tried to speak in Chinese. = Not knowing English. He tried to speak in Chinese.
第五，当从句的主语与主句的主语不一致时，从句可简化成分词复合结构作状语，还可简化成“with/without+名词/代词+分词短语”结构来作状语
【例】When the film start appeared, the children got exit. = The film start appearing, the children got exit.
第六，原因状语从句可以由形容词短语作状语来替代，放在句首或句尾，用逗号与主句隔开。

【例】As Tom was hungry and eager to have a rest, he went into the restaurant. = Hungry and eager to have a rest, he went into the restaurant.
11. 用介词表示因果关系
常用的介词有：because of，due to 和owing to。

因为都是介词，所以其后面不能接从句。

请比较：
1) We had an accident because he was careless.
2) We had an accident due to his carelessness.
3) Owing to his carelessness we had an accident
妙语点睛：在例句1中，因为是从句，所以用连词如because引导。

在例句2中，因为是名词短语his carelessness，所以用介词替换。

此处不能说due to he was careless*.在例句3中，同样是名词短语his carelessness,所以要用介词。

一般来说，owing to常置于句首，而due to通常不这么用。

精品译文：由于他的粗心大意，我们出了车祸。