His sister left home in 1998 and since .A. had not been heard ofB. has not been heard ofC

问题补充：

His sister left home in 1998,and since .

A. had not been heard of

B. has not been heard of

C. had not heard of

D. has not heard of

答案：

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：考察时态与语态。根据关键词since可知与完成时连用，且根据句意可知是被动语态。句意：他的妹妹在1998年离开家，从那以后就再也没有被听说过。故B正确。