问题补充:
—The poor people lived near the highway.
— very noisy.
A. It must have been
B. They must be
C. That might be
D. There must be
答案:
(答案→)A. It must have been
B. They must be
C. That might be
D. There must be
解析:根据句子的时态应该是过去时,因此排除B、D,再根据代词的用法,it可以用来指代环境,而that不行,因此选A。