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举一反三
【单选题】喷管出口流速计算式 的应用条件
A.
c f1 =0 ，任意工质，绝热流动
B.
c f1 =0 ， 任意工质，可逆绝热流动
C.
c f1>0, 任意工质绝热流动
D.
c f1> ，任意工质可逆绝热流动
【单选题】第二篇 Flying the Hypert Skies A little airplane has given new meaning to the term "going hyper. " The Hyper-X recently broke the record for air-breathing jet planes when it traveled at a h...
A.
It indicated the birth of a very fast airplane.
B.
It was self-powered, so it lasted only 11 seconds.
C.
It can transportcargo quickly and cheaply to the brink of space.
D.
It is a major milestone in the journey of making a new type of very fast airplanes.