治疗斑疹伤寒的首选药是
A.四环素
B.氯霉素
C.青霉素G
D.庆大霉素
E.红霉素
参考答案:A
—Who's the man over there? Is it Mr Black?
—It _____ be him. He's much taller. [ ]
A. can't
B. mustn't
C. should
D. may
患者男性,51岁,因反复心慌、胸闷半个月伴晕厥4次就诊。
该患者发生心律失常的电生理机制是()。
A.2相折返
B.0相折返
C.触发活动
D.自律性增高
E.3相折返