威爾斯美語員林分校

Let sleeping dogs lie. Do not instigate trouble.; Leave something alone if it might cause trouble. 别打草惊蛇

EX: Jill: Should I ask the boss if he's upset at my coming in late in the mornings?

   Jane: If he hasn't said anything about it, just let sleeping dogs lie.

Don’t look a gift horse in the mouth: This means that if you are given something, a present or a chance, you should not waste it by being too critical or examining it too closely.