问题
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
答案：B
B [考查时态。从for four hours以及下文的Let's have a rest.可以看出是谓语动词表示的动作到目前为止已经持续了一段时间并有可能继续下去，所以用现在完成进行时。]