the old man must()politely A.be spoken B.speak C.be spoken to D.be spoken

题目

the old man must()politely A.be spoken B.speak C.be spoken to D.be spoken

答案

C.be spoken to
此句是用被动语态表达如下一样的意思：
You（One） must speak to the old man politely.
你（或任何一个人）和长者说话时必须有礼貌.