because，since，as和for有什么区别

　　because\x0d\x0a　　because引导原因状语从句语气最强，表示直接原因,常用来回答由why提出的问题，所引导从句可放在主句前，也可放在主句后。例如：\x0d\x0a　　"Why did you do it?" "Because Carlos told me to".\x0d\x0a　　We can't go to Julia's party because we're going away that weekend.\x0d\x0a　　Because he didn't catch the last bus, he had to walk home.\x0d\x0a　　Why are you late for school ? Because I missed the first bus.\x0d\x0a　　\x0d\x0a　　as\x0d\x0a　　as “由于,鉴于” 主从并重，从句说明原因，主语说明结果。说明比较明显的原因。多用于日常语中，常译为“由于”，从句一般放于主句前。例如：\x0d\x0a　　You can go first as you're the oldest.\x0d\x0a　　As you don't feel well, you had better stay at home.\x0d\x0a　　As he wasn't ready in time, we went without him.\x0d\x0a　　I must stop writing now, as I have rather a lot of work to do.\x0d\x0a　　As it was getting late, I decided to book into a hotel. As it is raining, you'd better take a taxi.\x0d\x0a　　\x0d\x0a　　since\x0d\x0a　　since “因为,既然” 侧重主句，主句表示显然的或已知的理由。强调说话者和听者双方都知道的原因，常译为“既然”，一般用在这样的句子里。例如：\x0d\x0a　　Since we've got a few minutes to wait for the train, let's have a cup of coffee.\x0d\x0a　　Since you are not feeling well, you may stay at home.\x0d\x0a　　Since everybody is here, let's begin the meeting.\x0d\x0a　　Since I am a boy, let me carry the case.\x0d\x0a　　Since/As you are busy, you had better not go with us.\x0d\x0a　　Since we have no money, we can't buy that vase.\x0d\x0a\x0d\x0a　　for\x0d\x0a　　for “因为,由于”表明附加或推断的理由，引导的分句前常有逗号。for分句不放句首.是用来附带解释或说明前一分句的原因和理由。例如：\x0d\x0a　　Day breaks, for the cock crows.\x0d\x0a　　It must have rained last night, for the ground is wet.\x0d\x0a　　I won't go in, for my father is there.\x0d\x0a　　He must be ill, for he is absent.\x0d\x0a　　I went to see him, for I had something to tell him.

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for ,because,as,since这四个词作为连词,都有"因为"的意思,但它们在用法上有区别：
1、 because 是从属连词,接表示直接原因的从句,一般放在主句的后面,也可放在主句前面,它表示的语气最强,在回答why的问句时,必须用because.
例如：The swimming pool won't be open today because they're making repairs.
游泳池今天不开放,因为他们在修理.
Why did you move to France?
你们为什么搬到法国?
Because my father found work in Paris.
因为我父亲在巴黎找到了工作.
注意：在英语中用了because后,不可再用so.
2、 as 是从属连词,说明一般的因果关系,语气比because弱,说明比较明显的原因,它引导的从句通常放在句首,有时也可放在句末.
例如：As it is raining, you\'d better take a taxi.
天下雨了,你最好乘出租车.
3、since 意为"既然",表示对方已知的无需加以说明的原因或事实,语气比because弱,但是比as 强.
例如：Since we have no money, we can't buy that vase.
既然我们没钱,我们就不能买那花瓶.
Since everybody is here, let's begin our party.
既然大家都到了,那就开始我们的聚会吧!
4、for 是并列连词,用来附带解释说明前一分句的原因或理由,for引导的并列句,一般放在所要说明的句子的后面.
例如：I went to see him, for I had something to tell him.
我去见他,因为我有事要告诉他.
望采纳！