我知道不该这么说

know better than to───还没笨到；还不至于

the better to do sth───做某事更好

to be better than nothing───总比没有强

for better for worse───是好是坏

I have just had a marvelous steak, but know better by now than to say so.───我刚刚吃了一顿美味牛排，但我深知还是不说为妙。