星级典句：

第一句：That's all right.
没关系。

A: I'm sorry I forgot to bring the key of my room.
很抱歉我忘了带房间的钥匙了。
B: That's all right.
没关系。

第二句：It can't be helped.
这是没有办法的事。

A: I'm sorry I'm late. The train was delayed.
对不起，我迟到了。火车迟到了。
B: That's all right. It can't be helped.
没关系，这是没有办法的事。

没关系的表达法还有：

Don't worry about it. 别担心，不必介意。

It's nothing. 没关系。

There is no need to apologize. 没必要道歉。

It's not your fault. 不是你的错。