急性阿米巴病治疗首选药是（）
A.吡喹酮
B.四环素
C.甲硝唑
D.海群生
E.庆大霉素
参考答案：C
–– When did they arrive?
–– They ______two hours ago .They ______ here for two hours .
A．arrived; have arrived
B．arrived; have been
C．got; have been
D．reached; have reached
缺铁性贫血最常见的病因是（）。
A.慢性胃炎
B.慢性肝炎
C.慢性溶血
D.慢性感染
E.慢性失血
