Definition
Used to indicate that someone should do something, or it would be advisable to do something.
最好、应该
You had better start writing your report now, or you'll miss the deadline.
你最好现在开始写报告，否则你会错过截止日期。
We'd better leave early, so we don't miss the train.
我们最好早点离开，这样我们才不会错过火车。
You had best put on a coat; it's very cold outside.
你最好穿上外套；外面很冷。