We haven’t settled the question of _______ it is necessary for him to study abroad.为什么用whether不用if3Q~

问题描述:

We haven’t settled the question of _______ it is necessary for him to study abroad.
为什么用whether不用if
3Q~

因为前面是介词of

只用whether不用if的情况
后面or not 或to do 前面就用whether(或有明显的选择口气时 )
前面是介词 后面就whether
句首用whether(主语从句)
is后跟whether(表语从句)

因为后面有to study whether to do是短语