Question

because，since，as和for的区别

Answer 1

　　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.

Answer 2

because, as, since与for的不同用法：
相同之处：中文都表示“因为”，均为连词
区别：
（1）如果表示原因的状语从句语气较强，在整个句子中占重要位置，是句子的主要部分，一般用“because”。即回答why问句的提问，应用because。
1．Why did they come to China?
Because their father wanted to work in China.
（2）如果原因不重要，或为人所知，一般用as或since。它所引导的从句常常放在句首。
As you ask, I will tell you. 你既然问我，我就告诉你。
（3）for引导的表示原因的状语从句语气较because弱，类似一种补充说明，可有可无，一般不用它来回答why提出的问题。它引导的从句不能放在句首，而且前面一般用逗号与主句分开。
We can’ t go, for it’s raining. 由于天下雨，我们不能走了。

Answer 3

becaue since as和for表达原因时的区分