—When did Tom leave for Britain?        

—He’s _____ for two weeks.          [ ]

A. left    

B. gone    

C. been away  

D. leaving

抗绿脓杆菌感染的广谱青霉素类药物是

A．头孢氨苄
B．青霉素G
C．氨苄西林
D．羧苄西林
E．双氯西林