after ten years ,she changed a lot and look different from what he used to be是什么从句

问题描述:

after ten years ,she changed a lot and look different from what he used to be是什么从句
为什么不能用that引导呢?

宾语从句
因为从句中what作主语 而that在从句中不作成分 所以不用that再问一个问题,as air is to man ,so is water to fish ,第一个as为什么不能换成like ?