_____ you are my best friend, I'll tell you the secret, but it is only between you and me.

[      ]

A. Because of

B. According to

C. Now that

D. As if

肺炎链球菌肺炎治疗的首选抗生素是 ( )。

A．红霉素

B．庆大霉素

C．氧氟沙星

D．苄星青霉素

E．林可霉素