Student numbers have decreased by 500.
学生人数减少了500名.
Our sales are decreasing.
我们的销售量在减少。
An electromagnetic wave of audio frequency produced by atmospheric disturbances such as lightning, having a characteristically decreasing frequency responsible for a whistling sound of descending pitch in detection equipment.
啸声干扰一种由于诸如闪电等大气干扰而产生的音频电磁波, 具有典型的逐渐减弱频率的特征, 该频减引起了检波设备中调逐渐下降的啸声