While the swimmer's movements may be smooth and fluid, people have neither fins to stay afloat or generate speed, nor gills to deal with going under.

虽然游泳者的动作可能是平稳和流畅的，但人们既没有鳍来保持漂浮或产生速度，也没有鳃用于在水下呼吸。

youdao

So its very smooth very flat ice and you push a sledge on it and then you let go, what happens? The sledge keeps going. How can that be?

冰面很光滑，你推动雪橇，然后放手，接下来会怎样呢，雪橇仍然会继续前进，为什么会这样呢？

youdao

Everyday isn't going to be smooth sailing and there will be times when you want to throw in the towel.

每一天并不会一帆风顺的过去，也会有想要放弃的时候。

youdao

" We concluded: "Absolutely beautiful, velvety and smooth, like raspberry-chocolate fondue going down your throat.

WSJ: The Simple Truth About an Earthy Delight

But it hasn't always been smooth going for the 1, 200-employee closely held concern.

WSJ: Chobani Spawned the Greek-Yogurt Craze, Starting With One Small New York Factory

But we describe it, it's sort of like a swan, where we're kind of calm and serene above water -- but we're paddling like mad, going crazy underneath, trying to look smooth.

WHITEHOUSE: First Lady Michelle Obama Discusses State and Official Visits | The White House