had better(常简略为'd better)是一固定词组,had better"最好",用于表示对别人的劝告、建议或表示一种愿望.其用法有以下几点：
一、had better后面必须跟动词原形.
had better后跟动词原形(即不带to的不定式),构成had better do sth.句型.
这里的had不能用have来替换.如：
You'd better go to hospital at once.你最好立即去医院看病.
Tom,you'd better go there today.汤姆,你最好今天去那儿.
二、主语不论是第几人称,句子不论是什么时态,都要用had better的形式.如：
Now you(he,we) had better listen to the teacher.你(他,我们)现在最好听老师讲.
三、had better可用于的时态.
1.had better用于指现在.如：
Now you had better listen to the radio.你现在最好听收音机.
You had better be quiet.你最好安静一些.
2.had better用于指将来.如：
You had better start tomorrow.你最好明天动身.
We had better buy the more expensive one.It will last much longer and so it will be cheaper in the end.我们最好还是买贵些的,它更经久耐用,所以到头来,它还是更便宜些.
3.had better用于进行式,表示讲话人提出建议时,动作正在进行.如：
We had better be watching the TV play.我们最好现在就看到电视剧.
We had better be starting back now.我们最好现在就动身回去.
4.had better + have + V-ed可表示"本该做而没有做的事".如：
You had better have done it .如果你把那件事办妥就好了.(但实际上你没有那样做)
You had better have stayed with us .要是当时你和我们呆在一起多好啊.(实际上没有)
best ：[best]
形容词 a.(good和well的最高级)
1.最好的;最熟练的;道德最高尚的
I think John's plan is best.
我认为约翰的方案最好.
2.最适当的;最有效的
The best thing for you would be to forget it.
你最好是把这事儿忘了.
3.最大的;主要的
It took the best part of a day to get there.
花了大半天时间才到达那里.
副词 ad.(well的最高级)
1.最好地;最适当地;最有效地
I think Friday would suit me best.
我想星期五对我最适合.
2.最;极
My father knew best what was good for me.
我父亲最清楚什么对我有利.
名词 n.
1.最好;最佳[the S]
She always wants the best.
她总是要最好的.
2.最好(或最能干,最有名望)的人;最好的事物[M]
Even the best of us make mistakes.
即便是最能干的人也会出错.
3.(常用one's best)盛装
They wore their best to the party.
他们盛装赴宴.
4.(常用one's best)(某人的)最大努力;最佳状况
Although he failed,he has done his best.
他虽然失败了,可是他已尽了最大努力.
很详细的专业解释,希望采纳哦,我来自英语牛人团!
