the only thing that you should do is to try your best.语法有问题么?

题目

the only thing that you should do is to try your best.语法有问题么?
不知道语法上有没有问题!如果有的话 请指正!
我把the only thing that you should do 当成主语从句!

答案

语法上没有问题,其中to可以省略.
该句也为定语从句,先行词为thing