—What would I do if I can't sleep before a big exam?          

—You'd better            a long walk before going to bed.               [ ]

A. take              

B. taking                

C. to take

患者男，18岁。因腰痛，发热，尿频、尿痛而求治。检查后诊断为大肠杆菌所致的泌尿系感染，应该首先选择（）

A.诺氟沙星

B.红霉素

C.青霉素

D.头孢氨苄

E.苯唑西林