问题补充：
Jack’s grandfather for more than twenty years.
A. has dead
B. has died
C. has been died
D. has been dead
答案：
A. has dead
B. has died
C. has been died
(答案→)D. has been dead
解析：本题考查的是现在完成时态的用法，因为后接的是for+一段时间，所以需要动词为延续性动词，而die为短暂性动词，因而只能用用形容词表示状态与be动词连用。故选D
