all passengers —— to show thier tickets next time

问题描述:

all passengers —— to show thier tickets next time
A.require
B.is required
C.are required
D.are to require

选C.
句意:
下一次所有的乘客都被要求出示票据.
按照句意需要,应该是【被动语态】,排除A,D;
主语【all passengers 】是复数,排除B.