We haven’t settled the question of whether it is necessary for him to study abroad.这个句子是什么从句?为什么whether前面要加一个of呢?

问题描述:

We haven’t settled the question of whether it is necessary for him to study abroad.这个句子是什么从句?为什么whether前面要加一个of呢?

(We) haven’t settled (the question of) whether (it is necessary ) for (him to study abroad).
上面的括号是句子成份化分
whether 引导宾语丛句