表原因单词小结
一、because, since, as, for的用法区别
四者均可用来表示原因，区别如下：
(1) 关于 because：语气最强，表示直接原因，可用于回答 why 提出的问题、引导表语从句、用于强调句等，而其余三者均不行：
“Why didn’t he come?” “Because he was ill.”
“他为什么没来?”“因为他病了。”
My stomach hurts because I have eaten too many apples.
我肚子痛，因为苹果吃得太多。
That’s because you can’t appreciate music.
这是因为你不能欣赏音乐。
It is because he is honest that I like him.
是因为他诚实我才喜欢他。
(2) 关于 since 与 as：
a. 两者所表示的原因都是人们已知的，即对已知事实提供理由，而不是表示直接原因。since 比 as 语气稍强，且比 as 略为正式，它们引导的从句通常放在主句之前，有时也放在主句之后：
As you weren’t there, I left a message.
由于你不在那儿，我留了个口信。
Since you are wrong, you should apologize.
你既然错了，就应该道歉。
b. since 可用于省略句，而其他三者不行：
Since so, I have nothing to say.
既然如此，我无话可说。
(3) 关于 for：是并列连词(其余三者为从属连词)，它有时可表示因果关系(通常要放在主句之后，且可与 because 换用)；有时不表示因果关系，而是对前面分句内容的解释或推断(也要放在主句之后，但不能与because 换用)。比较：
The ground is wet, for (=because) it rained last night.
地面是湿的，因为昨晚下过雨。
It must have rained last night, for the ground is wet this morning.
昨晚一定下过雨，你看今天早上地面是湿的。 (此句不能用 because 代 for)
二、because与because of的用法比较
■从词性上看
because 是连词，其后接句子；because of 是复合介词，其后接名词、代词、动名词、what 从句等。如：
I didn’t buy it because it was too expensive.
我没有买是因为它太贵了。
He is here because of you (that).
他为你(那事)而来这里。
He lost his job because of his age.
由于年龄关系他失去了工作。
We said nothing about it, because of his wife’s being there.
因为他妻子在那儿，我们对此只字未提。
He knew she was crying because of what he had said.
他知道她哭是因为他说的话。
注意：because of 之后可接 what 从句，但不能接 that 从句或没有引导词的句子。如：
他因病未来。
误：He didn’t come because of he was ill.
误：He didn’t come because of that he was ill.
正：He didn’t come because he was ill.
正：He didn’t come because of his illness.
比较以下同义句：
他离开了这家公司，是因为老板在会上讲的话。
正：He left the company because of what the boss said at the meeting.
正：He left the company because of the thing that the boss said at the meeting.
我不能因为有个家就停止斗争。
正：I can’t stop fighting because I have a family.
正：I can’t stop fighting because of having a family.
■从用法上看
because 所引导的从句除用作原因状语外，还可用作表语。如：
It is because he loves you.
那是因为他爱你。
而复合介词 because of 所引导的介词短语通常用作状语而不用作表语。如：
他因雨缺席。
误：His absence was because of the rain.
正：His absence was due to the rain.
正：He was absent because of the rain.
但是有时若主语是代词(不是名词)，也可以用 because of 引出的短语作表语。如：
It is just because of money.
那只是因为钱的原因。
That was because of his sickness.
那是因为他生病的原因。
Practice today:
Choose the best answer for each of the following sentences
1. In some countries, ________ are called “public schools” are not owned by the public.
A. which B. as C. what D. that
2. ________ happens in the world makes us happy and sad by turns.
A. That B. What C. Which D. Whether
答案与解析：
1. C。本题考查what引导主语从句，并在主语从句中作主语。句意为“在许多国家，所谓的“公立学校”并非公众拥有。
2. B。本题考查引导主语从句的连接词。that引导主语从句只起连接作用，在从句中不作任何成分，无意义，但不能省略。what除引导主语从句外, 还在从句中作成分。which指一定范围内的“哪一个”；whether意为“是否”。根据句意“世上的事喜忧交替”可知答案为B。 |
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