We on it for several hours but we haven't yet reached any conclusion.
A. are working
B. work
C. have been worked
D. have been working
网友回答
A. are working
B. work
C. have been worked
(答案→)D. have been working
解析：考查时态。for+一段时间，与完成时连用，排除A、B；we与work是主谓关系，不应该使用被动语态，排除C；现在完成进行时可以表示动作有可能继续下去。句意：我们已经讨论了几个小时，但还没有达成任何结论。讨论有可能继续下去，用现在完成进行时较好，故选D。