had better do something

Từ điển Oxford Advanced Learner 8th

had better/best (do sth) idiom
used to tell sb what you think they should do.
• You'd better go to the doctor about your cough.
• We'd better leave now or we'll miss the bus.
•You'd better not do that again.
•‘I'll give you back the money tomorrow.’ ‘You'd better!’ (= as a threat)
Main entry: ↑better_idiom