高速旋转机械的起动试运转，开始时应作短时间试转，并观察其转速逐渐（）所需的滑行时间。
A.升高
B.运行
C.停止
D.降低
参考答案：D
多根多处肋骨骨折（）
A.反常呼吸
B.胸膜损伤后，空气进入胸膜腔异常通道自动闭合
C.肺裂伤破裂处形成活瓣，气体只能进胸膜腔而不能排出
D.胸壁伤口与胸膜腔相通
E.肺组织损伤血液积聚于胸膜腔
根据句意，用括号内所给单词的适当形式填空。
小题1:---How is your business going?
--- It couldn’t be _______ (bad).
小题2:Each of us _______ (breath) heavily after running on the playground every morning.
小题3:For everyone’s _______ (safe), we should always remember the law against driving after drinking.
小题4:Such a camera can help spacemen film _______ (they) during the flight.
