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。