He has been running.A. since two hoursB. for two o’clockC. two hours agoD. for two hours

问题补充：

He has been running.

A. since two hours

B. for two o’clock

C. two hours ago

D. for two hours

答案：

A. since two hours

B. for two o’clock

C. two hours ago

(答案→)D. for two hours

解析：在表示时间时，since后接时间点，表示自从……以来；for后面接一段时间，用于完成时态；ago用在一段时间之后，表示过去某个时间。句意：他已经跑了两个小时。结合语境可知选Ｄ。