问题
单项选择题
We（）on this project for four hours. Let's have a rest.
A. are working
B. have been working
C. worked
D. had worked
答案
参考答案：B
解析：
本题考查动词的时态，由“four hours”可知应用完成时态，排除A和C：由“Let's have a rest”可知工作还没完，因此应该用现在完成进行时。故选B。
