— The old man           for three months, didn't you know?

— Yes, I did. He           on January 7 th. [ ]

A. has died; has died

B. has died; died

C. has been dead; died

D. has been dead; has been dead

所谓平面矛盾是指一个油层在平面上，由于（）的高低不一，连通性不同，使井网对油层控制情况不同，注水后使水线在平面上推进快慢不一样，构成了同一层各井之间的差异。

A、渗透性

B、渗透率

C、孔隙性

D、孔隙率