so many representatives_ ,the conference had to be put off

问题描述:

so many representatives_ ,the conference had to be put off
a were absentb to be absentc being abse d had been absent
84.27(与题无关)
详细解释下,c选项 是absent

c
肯定不能是独立的句子,因为和后面一个完整的句子之间没有联接词,如 and ,but 之类的.
排除 a d
to be 一般表将来.排除b