however和but的区别：

1.However常表示“然而、可是”，but表示“但是”，however的语气比but弱。

However引出的内容与前文相比，显得比较出人意料、稍有不同。

而but引出的内容与前文相比，通常是截然相反或截然不同。

所以but的语气更强，常表示前后转折，意思相反相对，如前肯后否。翻译句子时，常翻译成“虽然......但是......”

Sam managed to finish the work before Monday. Tom, however,is still working on it.山姆已经在周一前完成工作了。然而，汤姆仍然在努力当中。

My grandpa is very old, but he is still quite strong.虽然我的爷爷非常老了，但是他仍然非常强壮。

2.However可放在句首、句中、句尾，要用逗号隔开。But不能用在句首，可用在句中。

The village is far away from the city. However,you can take a bus to get there.那个村庄远离城市。可是，你可以搭巴士去那。

The bike, however, takes a lot of time to repair.然而，这辆自行车需要花费大量时间修理。

The movie is really great. I have no interest in it, however.这部电影非常棒。然而我对它没有兴趣。

The rushed to the airport,but they missed the plane.虽然他们急忙赶到机场，但是他们错过了飞机。

1）but+完整句子时，but前常有逗号，后无逗号

He can’t do it, but you can（do it）.他做不了这件事情，但是你做得了。

2）But后面的成分不是句子时，前面不用逗号即可

He is old but strong.他虽然老，但是强壮。