（）对期货市场实行集中统一的监督管理。

A． 中国期货业协会

B．中国证监会

C．中国证券业协会

D．期货交易所

Most of the older civilizations which flourished during the fifth century B.C. are died out.

A．they have died out

B．has died out

C．have died out

D．they had died out