It's cold outside.Why------- stay at home.可不可以why don't you stay at home

可以.
why don't you stay at home?
=Why not stay at home?抱歉，打错了，为什么why not you stay at home 是错的这是固定句型：Why not +动词原形 .....?=Why don't you /we +动词原形......?意思是"为什么不……呢？" 所以why not you stay at home 是错的 【俊狼猎英】团队为您解答。