【什么语法】your excuse better be good

This better be good请问这句是什么语法结构? Your work is P____ good,but it could be better it is better to be good than to be just good looking什么意思 It had better be good. Your English is good ,but____ is better. This better be good .中文意思. This baby'd better be really good. To be good,better,best!老师教下吧! Eating vegetable[ ] good for your health [be]应添什么? ——i your good friend.be动词填什么 帮忙看看一句英语your life is betteryour grade should be better这句话语法什 excuse me,什么（be） you mark