It is not polite to interrupt when someone is talking.

打断别人说话是不礼貌的。

We are nothing if not polite.

我们一无所有，如果不是有礼貌。

It's not polite to point at others.

用手指着别人是不礼貌的。

It's not polite to stare at someone.

盯着某人看是不礼貌的。

It's not polite to interrupt a speaker.

打断别人的谈话是不礼貌的。