在交流电路中，电流的幅度是连续不断地变化的，因此相位和时间的概念变得十分重要了。
In ac circuits, the current amplitude changes continuously that the concept of phase or time becomes very important.
哥之间的交流，这在旧世界和新，改变了我们这个星球的历史大幅度永远。
This Columbian exchange, between the Old World and the New, changed the history of our planet drastically and forever.
若达到同样的引出时间，共振频率的交流电压的幅度可比直流电压值小一个量级。
To achieve the same extraction time, the amplitude of the ac voltage in the resonance frequency can be less than that of the DC voltage with one order of magnitude.
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