中原工学院 /
I sent invitations to 80 people, ______ have replied.
A、of whom only 20 of these
B、only 20 who
C、of 20 of these who
D、only 20 of whom
A、of whom only 20 of these
B、only 20 who
C、of 20 of these who
D、only 20 of whom
参考答案：