Professor James will give us a lecture on the Western culture but when and where yet.A.

问题补充：

Professor James will give us a lecture on the Western culture, but when and where yet.

A. hasn’t been decided

B. haven’t decided

C. isn’t being decided

D. aren’t decided

答案：

(答案→)A. hasn’t been decided

B. haven’t decided

C. isn’t being decided

D. aren’t decided

解析：考查时态及主谓一致。主语when and where作主语，谓语动词用单数，根据yet可知为现在完成时，选A。