sag curve

例句：

1. 1. The graph shows a sag curve at the beginning of the decline.
   图表显示在下降开始时有一个下垂曲线。
2. 2.The sag curve indicates that the economy is slowing down.
   下垂曲线表明经济正在放缓。
3. 3.The sag curve is caused by the weight of the material being pulled downwards.
   下垂曲线是由材料的重量向下拉造成的。