“风在吼，马在叫，黄河在咆哮”中的“吼”、“叫”、“咆哮”的声源分别是_______、_______、__________。
空气；马的声带；河水
Living in the mountain area has its problems, ________ obtaining water is a big problem.
A．of which
B．for what
C．as
D．whose
柴油机转速信号幅值范围为AC0∽20V。
