这句话的语法结构?是什么It is what you do once

题目

这句话的语法结构?是什么It is what you do once
It is what you do once in a while ,it is you do day in and day that makes difference .中的that makes difference 是实际主语吗?为什么前面没有that?

答案

强调句型结构：It is…that/ who（人）…… that（时间地点物等） who（人） It is in the shop that I bought this book.就是在那家商店我买了书 It is the boy who stole my car. 就是那个男孩偷...