1. John, if you don't learn how to keep your nose clean, you're going to end up in jail.
2. Let sleeping dog lie.
3. My brother is ill-tempered, and always stirs up trouble.
4. Don't always try to start something when everything is running smoothly.
5. Don't trouble troubles till trouble troubles you!
6. Don't ask for trouble. You'd better run away.
7. He hasn't made a lot of changes to the team since taking over as head coach, figuring if it ain't broke, don't fix it.
ain't [eint] prep. 不是（等于are not，am not）
8. Do not get involved with politics. That's borrowing trouble.
9. I don't want to make trouble, but I have a few suggestions that could make things work more smoothly.
10. Don't go looking for trouble.