Пожалуйста проверьте правильно ли вставлены в конце предложения a verb + away or back.

1. I haven't seen our neighbours for a while. I think they must GO BACK.
2."I'm going out now". "OK.What time will you GO AWAY?
3. A man was tryinh to break into a car. When he saw me, he WENT BACK.
4. I smiled at him, but he didn't GO AWAY.
5. If you cheat in the exam, you might GO BACK with it. But you might get caught.
6. Be careful! That's an electric fence. Let's go away from it.