企源知识库

—I‘ve been told to pay the rent.
—But it‘s already been paid. It ______ by someone else.
A、must be
B、may be
C、must be paid
D、must have been paid
【正确答案】：D
【题目解析】：must have 表示对过去的推测 ；pay 与rent 为被动关系，因此此处要使用被动语态，D 符合题意。