In many countries, government reports, legal papers and most business letters are the main situations _______ English is used.

A．that

B．when

C．which

D．where

对于青霉素高度耐药的肺炎球菌肺炎，应首选的抗生素是（）

A.头孢唑林

B.阿莫西林

C.氨苄西林+棒酸

D.头孢曲松

E.红霉素