我是在降价期间或一月份降价期内买这件物品。 I bought this in the sale or at the sale or in the january sale.
根据时间或幅度选择波形的一部分，即在一个特定的间隔里一个波形允许另一个波形通过电路的动作。 Selection of part of a wave on account of time or magnitude. Operation of a circuit when one wave allows another to pass during specific intervals.