喷射泵是以一种利用工作流体的射流来（）水泵与吸水管中的空气，实现引水的真空泵。
A.吸入
B.排出
C.吸收
D.释放
参考答案：B
It’s ___ time that he has failed in the experiment,However, he has made up his mind to try ___ time next week.
A．the first.. a second
B．a first.. the second
C．for the first.. second
D．the first.. second
幽门螺杆菌的培养条件不正确的是（）
A.微需氧
B.营养要求低
C.需一定湿度
D.需要CO2
E.需血清或血液
