what you should do is try to do everyting well

题目

what you should do is try to do everyting well
为什么加what?

答案

这个句子本身有点小问题.
what you should do is TO try to do everyting well.
其中what you should do是主语,is是谓语动词,to try to do everyting well是不定式短语作表语.