If there ______no buying and selling of animals, there ______no killing in nature.

A．is, will be

B．will be, will be

C．is, is

D．will be, is

以下作用于细菌细胞壁的药物是（）

A.阿奇霉素

B.阿米卡星

C.利奈唑烷

D.哌拉西林

E.氧氟沙星