英语语法知识求助：句子是i sent invitations to 80 people,__have replied.句子是i sent invitations to 80 people,__have replied.A of whom only 20 of themB only 20 of them whoC of whom only 20 D only 20 who改选哪个呢?这是什么语法知识呢?
问题描述：
英语语法知识求助：句子是i sent invitations to 80 people,__have replied.
句子是i sent invitations to 80 people,__have replied.
A of whom only 20 of them
B only 20 of them who
C of whom only 20
D only 20 who
改选哪个呢?这是什么语法知识呢?
答