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

税负不容易转嫁的情形是（）。

A.生活必需品

B.课税范围广泛

C.非生活必需品

D.课税范围狭窄

E.需求弹性小，供给弹性大