[单选] 确定信号可以用（）表示。

额定功率是信号源所能发出的（）功率。 最大。 最小。 0。 You are underway in reduced visibility.You hear the fog signal of another vessel about 20° on your starboard bow.Risk of collision may exist.You should（）. alter course to starboard to pass around the other vessel。 reduce your speed to bare steerageway。 slow your engines and let the other vessel pass ahead of you。 alter course to port to pass the other vessel on its portside。 正电阻可以看作为（）能量的能源。 消耗。 提供。 不消耗也不提供。 （）is the main reason that reduces the power advantage of a two-stroke engine over a same size four-stroke one to about（） Inefficient scavenging；twice。 Inefficient scavenging；1~8 times。 Fewer strokes in a circle；twice。 Fewer strokes in a circle；1~8 time。 收音机的中频放大器通频带约为（） 6-8khz。 5-9khz。 40-50khz。 确定信号可以用（）表示。