【题目】They are trying to make sure that 5G terminals_________ by 2022 for the Beijing Winer Olympics.
A. will installB. will have been installedC. are installedD. have been installed
在线课程【答案】B
【解析】
考查时态和语态。句意：他们正努力确保在2022年北京冬奥会之前安装5G终端。表示在将来某一时间以前已经完成或一直持续的动作，用将来完成时。“5G终端”和“安装”之间是被动关系，用被动语态，故选B。