You'd better shape up if you want to stay on.
shape up直译过来就是：“塑造好的形象”，这个短语的正确意思是：“好好表现，好好干”。因此，当美国人说"You'd better shape up if you want to stay on."时，他/她要表达的意思就是:"You must performwell if you want to keep this job."、"You have to behave yourself if you don't want to getfired."。
Terry: My boss always asks me to go on business. I can't bear it.
Benjamin: Buddy, you'd better shape up if you want to stay on. Never fight against your boss.
①I protest about having to work overtime every night.
②Since the boss isn't here, how about getting off earlier?
③The manager has formed an unfavorable opinion of my work. This is unbearable!
④Don't nose into other people's business.
1. shape up 表现良好
Girls are being recruited now. I heard they are shaping up very well.
It is no use simply to tell adolescents to shape up and do something useful.
I'm now giving you a last chance either shape up or ship out.
2. nose into 打听，查探
Do not nose into other people's private life.
Why do you always nose into other's affairs?
I don't like the kind of people who always nose into other people's affairs.