治疗肺炎链球菌肺炎应首选的抗生素是（）
A.红霉素
B.青霉素
C.复方磺胺甲基异噁唑
D.氟喹诺酮类
E.头孢菌素类
参考答案：B
在我国慢性胰腺炎的主要病因为（）。
A.免疫疾患
B.胆道疾患
C.特发性
D.慢性酒精中毒
E.遗传性
–What was your brother doing at this time yesterday?
–He was reading a magazine ________ I was writing an e-mail at home.
A．as soon as
B．after
C．until
D．while
