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

对已存入出口监管仓库因质量等原因要求更换的货物，经仓库所在地主管海关批准，可以更换货物。被更换的货物在原存放货物出仓后入仓，并应当与原货物的商品码编、品名、规格型号、数量和价值相同。