2018年6月大学英语四级语法：had better

英语自学网

　　had better表示"最好"
        　　had better 相当于一个助动词，它只有一种形式，它后面要跟动词原形。
        　　had better do sth
        　　had better not do sth
        　　It is pretty cold. You'd better put on my coat.
        　　She'd better not play with the dog.
        　　had better have done sth表示与事实相反的结果，意为"本来最好"。
        　　You had better have come earlier.