—Did any signs e up before the earthquake?
—Yes. Unusual things all those days. For example, a number of animals got out their homes.
A. happening
B. were happening
C. has happened
D. had happened
网友回答
A. happening
(答案→)B. were happening
C. has happened
D. had happened
解析： 句意：--在地震来临前有什么迹象吗？--是，不寻常的事情那些天一直在发生，例如：很多动物会从家里出来。这里的时间状语是all those days.指的是过去发生的地震前的一段时间，所以是过去的一段时间一直发生的事情，所以用过去进行时。选B。