Some people believe that boys are cleverer than girls.This is not necessarily the case,however.

题目

Some people believe that boys are cleverer than girls.This is not necessarily the case,however.
这里的necessarily 为什么是副词..而是不是形容词形式?

答案

this is not the case
这是个完整的句子
用 necessarily 修饰整个句子
所以是副词形式了