His sister left home in 1998, and ever since.
A. had not been heard of
B. has not been heard of
C. had not heard of
D. has not heard of
网友回答
A. had not been heard of
(答案→)B. has not been heard of
C. had not heard of
D. has not heard of
解析：考察时态语态。根据句意可知，sister与hear of之间是被动关系，根据since可知，要用现在完成时
句意为，他的姐姐在1998年离开了家，并且自从那时就没有她的消息了