you＂d better即you had better后面加动词原型 (即不带to的不定式)，构成you had better do sth.句型。意思是"你最好做某事”。

had better do sth. 最好做某事。这是固定搭配, 适用于各种人称和数。 had可与主语缩写也可不缩写。

better英 [bet(r)] 美 [bt] ；adj.较好的;更合适的;能力更强的;好转的

adv.更好地;更;更妥；v.胜过;上进；n.更好者;更有才智者

第三人称单数： betters 复数： betters 现在分词： bettering 过去式： bettered

过去分词： bettered

例句：

1、I think you'd better tell us why you're asking these questions.

我想你最好告诉我们你为什么要问这些问题。

2、Now that you are here, you'd better stay.

既然你已经来了，最好还是住下。

3、Maybe you'd better tell me what this is all about

也许你应该告诉我这究竟是怎么回事。