高等继续教育 / 统考英语B
正确率:统考%
题型描述: 单选题
A. must be busy to work
B. must have been busy working
C. must be busy wording
D. would have been busy working
He didn’t show up at the party yesterday. He ____ in the lab.
A. must be busy to work
B. must have been busy working
C. must be busy wording
D. would have been busy working
参考答案: