Though we don’t know what was discussed yet we can feel the topic.A. had changedB. will c

问题补充：

Though we don’t know what was discussed, yet we can feel the topic.

A. had changed

B. will change

C. was changed

D. has been changed

答案：

A. had changed

B. will change

C. was changed

(答案→)D. has been changed

解析：从what was discussed，可知事情已经发生。从can feel可知说的是现在的情况。应用完成时，表示过去一动作对现在造成的影响。又topic 对change是被动关系。故选D。