to return to a place after you have been somewhere else

If you get back in time, you can come with us. 如果你能及时赶回来，你就可以跟我们一起去。

When we got back to the hotel, Ann had already left. 当我们回到旅馆时，安已经走了。

to do something unpleasant to someone because they have done something unpleasant to you

I'll get you back for this, just you wait! 你这样对我，我会报复的，你就等着吧！

I think he's trying to get back at her for those remarks she made in the meeting. 我认为，他因为她在会上说了那些话而在想方设法报复她。

to be given something again that you had before

He went next door to get his ball back. 他到隔壁去取回他的球。

Don't lend him money - you'll never get it back. 别借给他钱，你会永远要不回来的。