对once提问要用什么疑问词

问题描述:

对once提问要用什么疑问词
急啊,知道的快帮帮忙呗,感激不尽啊~~~~~~~~~

对once提问应该用how often
例句 ①:-How often do you go to KFC
-Once a week.
例句 ②:-How often do you see Mr.Jack in our new term?
-Only once.