You could be better and you have to be better.这个句子对么?

问题描述:

You could be better and you have to be better.这个句子对么?
我想写一个意思是“你可以做的更好并且你一定要做的更好”的句子,上面这个句子是对的么?如果不对,该怎么写?

把have.to改成must更好