The mittee over the problem among themselves for two hours.
A. has argued
B. has been arguing
C. have argued
D. have been arguing
网友回答
A. has argued
B. has been arguing
C. have argued
(答案→)D. have been arguing
解析：本题的关键词是后面的时间状语for two hours，该时间状语常常和现在完成时，或者现在完成进行时连用。表示动作从过去发生一直持续到现在，而且还在发生。句义：在两个小时里，委员会一直都在讨论做过问题。现在完成进行时强调动作的持续性。故D正确。