Let a thing slide直译过来就是：“让事物自然滑动”，这个短语的正确意思是：“让事情顺其自然”。因此，当美国人说"Let a thing slide."时，他/她要表达的意思就是:"Let the thing go as it does."、"Leave it as it is."、"Let it be."。
Jane: Shirley, I have been working so hard but I can't get a raise or promotion. How frustrating!
Shirley: Let a thing slide. Everything would be OK.
①I'm sorry to hear that you missed the opportunity to get promoted.
②I have been an editor for over five years without any promotion.
③I got a pathetic year-end bonus, but half a loaf is better than no bread.
④He prefers to promote those apple polishers.
1. frustrating adj. 令人沮丧的
The current situation is very frustrating for us.
It's really frustrating when everything I try to do fails.
2. bonus n. 资金
Workers in big firms receive a substantial part of their pay in the form of bonuses and overtime.
The bonus represents how much the boss appreciates your hard work .
3. apple polisher 马屁精
He was promoted very quickly because he is a real apple polisher.
She is a real apple polisher for the way she's crawling around the boss and making eyes at him.