中枢兴奋药主要用于
A．呼吸肌麻痹所致呼吸抑制
B．中枢性呼吸抑制
C．低血压状态
D．支气管哮喘所致呼吸困难
E．惊厥后出现的呼吸抑制
参考答案：B
An inflatable liferaft can be launched by（）.
A.the float-free method ONLY
B.breaking the weak link on the painter
C.throwing the entire container overboard and then pulling on the operating cord to inflate the raft
D.removing the securing straps
DZ型中间继电器的保持电压不大于80%UN。（）
