矿井风流中氨气浓度不超过（）%。

入风井和采掘工作面的新鲜风流含尘量不得超过（）mg m3。

A.0.5
B.1.5
C.2.5
D.3

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听力原文：W: Can you tell me the least expensive way to get to New York City?M: If you go by bus it's only $ 25. But if you go by train, it's almost twice that much.Q: What does the man mean?(16)A．The train is cheaper than the bus.B．The bus is cheaper than the train.C．There are two buses every day.D．The train is faster than the bus.

A.
Q:
B.The
C.
B．The
D.
C．There
E.
D．The
F.

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