Vertical migration in the ocean is the largest net animal movement on our planet.

海洋中的垂直迁徙是地球上最大的动物净迁徙。

In a healthy heart, the net movement is downward and slightly left.

在健康的心脏中，净运动向下，稍微向左。

This is because the net movement of the heart's impulses is toward lead II, making it the best general view.

这是因为心脏脉冲的净运动朝向第II导联，从而使其成为最佳的全视图。

Even though there's not much net movement of the water, the ducky drifts with the waves, and pretty quickly is pushed into the bullseye.

尽管水没有太大的净运动，鸭子还是随着波浪漂流， 很快就被推入了靶心。