Perhaps the U-bend is merely an expression of the effect of external circumstances.

也许u型轨迹只是外部环境造成影响的一种表示方法。

youdao

This effect explains why a straw in a glass of water appears to bend at the surface of the water.

这种作用解释了为什么看起来玻璃杯中的吸管在水面处弯曲。

youdao

Since then, interest in the U-bend has been growing. Its effect on happiness is significant-about half as much, from the nadir of middle age to the elderly peak, as that of unemployment.

此后，人们对马蹄形趋势的关注日益增长，它对幸福感的作用十分显著，从处于最低端的中年时期到达随后的顶峰年纪，正如失业率趋势一样，且具有全球普遍性。

youdao

He also possesses a remarkable and unique free-kick technique, managing to bend and swerve the ball to devastating effect, notably with the goal that effectively ended Arsenal's challenge in the semifinals of this year's Champions League.

CNN: Profile: Cristiano Ronaldo

The effect seems to combine the function of a vase with the bend of a flower stem.

WSJ: Finding Tomorrow's Heirlooms Today | Weekend Journal Gift Guide | Design