because用作连词，基本意思是“因为”,强调直接造成某种结果的理由和原因。可引导状语从句和表语从句，也可用于强调句和省略句。

1.because的基本意思是“因为”,强调直接造成某种结果的理由和原因,所引导的原因状语从句多置于主句之后,有时为了强调,也可置于主句之前,并用逗号与句子的其他部分隔开。

I study because I want to learn.

我学习是因为我想学到知识。

Just because they make more money than I do, they think they are so superior.

只因为他们挣钱比我多,他们就认为自己高人一等。

2.because还可用来引导让步状语从句,这时,通常用于否定句或疑问句中。

Because the husband is vile—should the wife be vile too?

做丈夫的不正派,是不是做妻子的也应不正派呢?

3.because有时还可引导表语从句。

This is because the earth is travelling round the sun.

这是因为地球在围绕太阳运转。

This is because the direct current flows in a wire always in one direction.

这是由于直流电在导线内总是沿着一个方向流动。

4.because可用于强调句。

It is because he is honest that we like him.

是因为他诚实我们才喜欢他。

5.not...because...结构有时否定主句，有时否定从句，须根据上下文正确判断。一般来说，否定主句时because前多有逗号，而如果because前有just，则多半否定从句。

I didn't go, because I was afraid.

我没有去是因为怕。

Because I was ill,I didn't go to school yesterday.

因为病了,所以昨天我没有去上学。

6.because可用于省略句

The room was uncomfortable because too hot.

因为太热，这房间很不舒服。