If you are not sure ___ a woman is married or not,it is always safe to use the title Ms.
问题描述：
If you are not sure ___ a woman is married or not,it is always safe to use the title Ms.
这里可以用if 开头那个If 没起到什么影响吧
题目给whether和if两个选项然后答案选whether、
但是or not没有紧跟在其后
所以我想问这里可以用if
答
If you are not sure (whether) a woman is married or not,it is always safe to use the title Ms.
这里不能用if,因为后面有or not,所以只能用whether,or not不一定要紧跟在whether后面,只要句子后面有or not就要用whether.另外,开头的if引导的是条件状语从句,对后面的成分没有影响.那在非正式口语中可以用if吗这个不是很清楚，我只知道这里不能用if.好吧