The roads are wet,You()drive slowly选择had ratherwould ratherhad betterwould better为什么选had better?而不是would rather?

had better 是“最好怎么样”，意思是：路是湿的，你最好开慢点。而would rather一般与“than”连用，是“宁愿”连用。

had better do sth 表示最好做某事，是给别人的建议，用在此处合适，因为路面很滑，所以最好开慢点儿。
而would rather表示宁愿做某事，如果主语是I的话就可以了，但主语是you，很明显是给别人的建议，那只能用had better

这道题的正确答案是：
had better 是好
would rather是宁愿
这里是对别人的建议,所以是最好怎么做
had better to sth 最好做某事
路很湿滑,你最好开慢点.