声速的变化取决于传播媒介的不同,为了获得更加精确的测量结果,超声波液位仪表可以由程序设定不同媒介的声速。
参考答案:对
You board an inflatable liferaft that has been hand launched from a sinking vessel. What should you do first after everyone is onboard the liferaft?().
A.Cut the painter
B.Operate the radio equipment
C.Open the equipment pack
D.Ventilate the liferaft of CO2
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