as 和because表原因的时候用法有什么不一样的?

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：
"Why did you do it?""Because Carlos told me to".
We can't go to Julia's party because we'regoing away that weekend.
Because he didn't catch the last bus, hehad to walk home.
Why are you late for school ? Because I missed the first bus.
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：
You can go first as you're the oldest.
As you don't feel well, you had better stayat home.
As he wasn't ready in time, we went withouthim.
I must stop writing now, as I have rather alot of work to do.
As it was getting late, I decided to bookinto a hotel.
As it is raining, you'd better take a taxi.
拓展：since和for也能表示原因
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：
Since we've got a few minutes to wait forthe train, let's have a cup of coffee.
Since you are not feeling well, you maystay at home.
Since everybody is here, let's begin themeeting.
Since I am a boy, let me carry the case.
Since/As you are busy, you had better notgo with us.
Since we have no money, we can't buy thatvase.
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：
Day breaks, for the cock crows.
It must have rained last night, for theground is wet.
I won't go in, for my father is there.
He must be ill, for he is absent.
I went to see him, for I had something totell him.

你好，我给你说一下他们怎么区分吧，这是我的语法书上的，并且很权威的哦！
as：由于，鉴于。主从并重。从句说明原因，主句说明结果。
because：因为。表示直接原因，这个原因受到特别的强调，一般位于主句之后，还可回答why的提问。
例句：1.As I knew he was ill,I did not call.我知道他病了，没给他打电话。2.I like Tom because he is kind.我喜欢汤姆因为他是和蔼的。

祝你好运，希望能采纳我的答案哦~

pa