_________ something wrong with my bike. Can I use yours?

A．It is

B．It was

C．There is

D．There was

患者，男，57岁。右足划伤3天，局部沉重疼痛，持续加重，迅速向上蔓延，伤口大量液体渗出并可见气泡冒出。应首选的抗生素是（）

A.甲硝唑

B.青霉素

C.妥布霉素

D.氧氟沙星

E.庆大霉素