Question

All but one ＿＿ take part in the conference ＿＿ tomorrow. A．is

Answer 1

D

all but one 主语是all，且all在此指人，故谓语动词用复数；take place 属不及物动词短语，无被动语态；be about to后面不能跟具体的时间状语。