Joints need cartilage for smooth movement and to absorb shock when you put pressure on a joint.

VOA: special.2010.05.19

From 1983 to the present as you just said, the economy has a long period of smooth, robust expansion interrupted by two very mild recessions.

第二时期是从1983年至今，正如你所说，经济长时间处于,平稳强健的发展状态,而只出现了两次轻度衰退。

斯坦福公开课 - 经济学课程节选

Like I said, it's very smooth, very polite.

就像我说的，这种说法非常礼貌与流畅。

Why don't 课堂 - SpeakingMax英语口语达人

If I smooth out the bumps now then the path ahead is sure to be smooth, right?

FORBES: Does Confidence Grow On Trees?

Well actually, the Hobbit preview wasn't shaky, it was smooth -- maybe too smooth -- and that's the point.

ENGADGET: Editorial: Despite shaky 48 fps Hobbit preview, high frame rates will take off

Then, on a smooth. flour-free surface, roll the ball under the palm of your hand until the dough is smooth and firm -- about 1 minute.

CNN: Pizza Dough