英语难题：I am sure everyone can do this easily if he wants to 请问后面if he wants 后面为什么还要加
问题描述：
英语难题：I am sure everyone can do this easily if he wants to 请问后面if he wants 后面为什么还要加
为什么还要加to?
最好给几个例句
答
to 在这里代替整个不定式if he wants to do this ,以避免重复