but 是我们熟悉的并列连词，常常用于连接两个并列的句子。

比如: Peter hasn’t got a car, but his sister has. (彼得没有车，但他姐有。) but 除了用于连接两个句子外，还可用于连接句子成分。

but是但是的意思，用在转折句中，如：. Dick seldom talks of anything but music.

She looks very young, but she is already in her 30's.