在上下班高峰时间，城市的交通混乱不堪。

The traffic in the city is chaotic in the rush hour.

《牛津词典》

在上下楼时，我们需要走右边，留下左边的空间给那些匆忙的人。

When going upstairs or downstairs, we need to walk on the right, leaving the left space for the people who hurry up.

youdao

他的飞机在上下翻飞时画出了一条美丽的曲线。

His plane swooped a beautiful curve up and down.

youdao

Well, how do you get this hearts to move up and down and seemingly in these random patterns?

但是，你怎样才能让这些爱心们看起来,像是在某种随机的模式下上上下下地移动呢？

哈佛公开课 - 计算机科学课程节选

He was motionless, all but for one finger that moved up and down in front of his face as if he were marking time with it.

他一动也不动，除了一根手指在他的面前上下摆动,好像在用它标记时间。

耶鲁公开课 - 1945年后的美国小说课程节选

It's so inappropriate and ghoulish, I think, in this already sufficiently ghoulish context.

它是这么不合时宜，这么残忍，在这本来就够残忍的上下文中。

耶鲁公开课 - 弥尔顿课程节选