You have no idea how hard it's been to stay away.这么久不能回来，我真的很难过

stay away不在家, 离开

Why did you stay away from school?

你为什么缺课?

The naval officer asked him to stay away from the base.

那位海军军官让他离开基地。

I'm just not sure about them.但是她们就不一定了

sure about对 ... 确信的

I'm not really sure about that.

我对此不太肯定。

Forgive me, but are you sure about the agreement?

请原谅，但是你对那个协议肯定吗？