实用英语语法 第二十七讲（状语从句 原因 结果 目的状语从句）
实用英语语法
第二十七讲
原因，结果，目的状语从句
原因状语从句
这也是最为常见的一种从句，我们常用因果关系法支持自己观点
通常由because, since, now that, as和for等引导
I had to stay at home because/since/as it was raining heavily.
我不得不呆在家里，因为雨下得很大。
Because I had been caught up in the traffic jam, I was late for work this morning.
因为被堵在路上，所以我今天早上上班迟到了。
Since it"s a long journey, we"d better go there by air.
因为旅途很长，我们最好乘飞机去。
As we can work out the proplem, we"d better turn to our teacher.
既然我们能解决这个问题，我们最好去找老师。
Now that(=Since) you"ve realized your mistake, you must apologize to her.
既然你认识到了自己的错误，你必须向她道歉。
He walks with the help of a guide dog, for he is blind.
因为是盲人,他在导盲犬的帮助下走路。
尽管because, since, as都可以表示原因，有时候可以互换。但是我们要很多时候还是要尽量区别使用： 说明直接原因，或人所不知的原因，最好用because；why提出的问题必须用because回答。当原因是显而易见的，或已为人们所知，可以用as或 since。例如：
-Why do they look so upset?
-Because they lost the game. I didn"t go out, because I was afraid of the dark. You should give way to her since/as she is an old lady.
Since /As an power failure occurred, the concert had to be cancelled.
Since /As she wants to be a doctor, she decided to study Medicine at college.
for表示原因，也需要我们注意：
如果不是说明直接原因，而是多种情况加以推断，就只能用for：
He must be ill, for he is absent from work today.
他一定是病了，因为他今天没有上班了。
在上面这个例句里，没上班明显不是生病的原因，反而是生病的结果。是根据他旷工来推断他生病了。
for 引导从句不能放在句首，主要用来补充新信息；because从句如果放在句末也可以用for：
I decided to see a doctor becausefor I didn"t feel well.
我决定去看医生，因为我感觉不舒服。 I had to stay at home and study – for the exam was soon.
我不得不呆在家里学习——因为很快就要考试了。
结果状语从句
结果状语从句常由so…that 或 such…that（如此...以致...）引导。
Ben was so angry at her that didn"t speak to for a whole month.
本对她很生气，一整月都没和她说话。
The boy is so brave that he stopped the robber from robbing the old lady.
这个男孩很勇敢，阻止了强盗抢劫老太太。
Our maths teacher is such a serious person that we"ve never seen him smile.
我们的数学老师是个严肃的人，我们从未见过他微笑。
It"s such cold weather /a cold day that we had to gather around the fireplace.
Mr and Mrs Smith are such nice people that we all like them.
史密斯先生和夫人真是很好的人，我们都喜欢他们。
such…that...里such后面如果是 a/an + 形容词+ 单数名词，可以与so…that句型转换：
It"s such an interesting story that I read it though in one night.
这故事非常有趣，我一个晚上就读完了。
= It"s so interesting a story that I read it though in one night.
He is such a good teacher that all his student respect him.
他是个好老师，他的学生都尊敬他。
= He is so good a teacher that all his student respect him.
含不可数名词和复数名词，无法互换。
so…that...句型如果主从句主语相同，可以与too...to...句型转换：
The girl is so young that she couldn"t go to school.
这个女孩太小了，不能上学。
= The girl is too young too go to school.
He is so shy that he never talks first to another person.
他很腼腆，从不先和别人说话。
= He is too shy to talk first to another person.
注意：many和much+名词，前面只能用so:
There are so many books in the library that we should select some to borrow.
图书馆里有那么多书，我们应该挑选一些借阅。
People are faced with so much stess today that some become depressed.
如今人们面临着太多的压力，有些人患了抑郁。
目的状语从句 表示目的状语的从句可以由so that, in order that, lest, for fear that, in case等词引导。
We should all go to work more by bus so that there will be less air pollution.
我们都应该多乘公共汽车去上班，这样空气污染就少了。
They decided to drive by themselves to Qiandao Lake so that they can enjoy the view along the way.
他们决定自己开车去千岛湖，以便沿途欣赏风景。
Take an umbrella with you in case it rains in the afternoon.
带把雨伞，以防下午下雨。
We take a family vacation in the country each year, in order that the children learn to appreciate nature"s beauty.
我们全家每年都去乡下度假，以便孩子们学会欣赏大自然的美丽。
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