题目内容
They are still working in the field. They ________ for two hours.
A. had been working
B. have been working
C. worked
D. are working
答案:B
练习册系列答案
相关题目
题目内容
They are still working in the field. They ________ for two hours.
A. had been working
B. have been working
C. worked
D. are working