．Many in the credit industry expect that credit cards will eventually ________ paper money for almost every purchase.

A.exchange   B.decrease                   C. trade                          D replace

下列描述中对细菌L型描述正确的是（）。

A.细胞壁缺陷，在高渗环境中难以存活

B.L型细菌的形态单一

C.革兰染色阳性

D.在L型细菌专用培养基上典型菌落可呈荷包蛋样

E.由于细胞壁缺陷，细菌L型无致病力