“She’s here to ask for help,isn’t she?” he asked.

题目

“She’s here to ask for help,isn’t she?” he asked.
这题变成间接引语后就是He asked whether she was there to ask for help or not.
这里为什么要用whether or not?可以用if 代替么

答案

whether or not “是否”,固定搭配
可以用if代替,句子变为：
He asked if she was there to ask for help .