Stupid is as stupid does.蠢人做蠢事 这是俚语或习语类句子,对于可尝试理解它的句式结构及语法,但有些约定俗成的不能完全用语法来解释清楚；
但as连词类似用法可以举例：
what he says as what he does
His saying is as he does