例如当我想让一个物体像相反的方向移动，我首先需要让它慢下来，然后在推动它向另外一个方向移动。

If I wanted to reverse an object's momentum, I first had to slow it down before I could get it moving in the opposite direction.

youdao

在一个时期，表层和次表层的水流方向相反；表层水流向外海方向流动，靠近底层的水流则向陆地方向流动。

For a time, surface and subsurface current are in opposite directions; flow is seaward at the surface and landward near the bottom.

youdao

与热量在金属材料中可以向各个方向传导有所不同，这种制程能够令热量在这些聚合物中只沿着某一个方向传导。

The process does endow the polymer to conduct heat in only one direction, however, unlike metals which conduct equally well in all directions.

youdao

At infinity, there's no stored potential energy, and it drops off more and more negative as one over R.

在无限远处，没有储存的势能，并且它向负方向减少，当距离超过R时。

麻省理工公开课 - 固态化学导论课程节选

But, you know, in 2D, the options are not just left and right or north and south, but infinity of possible directions in which I could go those 5 km.

但在二维空间中,不仅可以向左向右或者向南向北,我在走那5公里的时候可以有无数个方向

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