噬菌体侵染细菌的实验证明了[ ]
A．蛋白质是遗传物质
B．DNA是遗传物质
C．DNA是主要的遗传物质
D．DNA是转化因子
答案：B
______ two giraffes，Zheng He later brought zebras，shells，elephant ivory back to China after his voyages.
A．Besides that
B．Except
C．In addition
D．Apart from
肾损伤非手术疗法应除外
A．抗休克治疗
B．密切观察
C．应用止血剂，止痛和镇静剂
D．抗感染治疗
E．尿转清后即可下床活动
