She needs to feel whether something is rough or smooth.

她需要感觉某物是粗糙的还是光滑的。

youdao

This paint will adhere to any surface, whether rough or smooth.

这种油漆能附着于任何粗糙或光滑的表面。

《新英汉大辞典》

He'll stroke his tie or smooth a lapel.

他会抹领带，或是抚平上衣衣领。

youdao

Or,they place long thin rolls of clay on top of each other and then make them smooth.

VOA: special.2009.09.09

Somehow, if you could manufacture a really smooth frictionless surface, that if you took a hockey puck or something and an air cushion and you give it a push, in some idealized world, it'll travel forever.

如果你制造一个绝对光滑无摩擦的表面,然后在上面放个冰球或者别的什么,或者气垫,然后推它一下,在理想条件下,它会永远运动下去

耶鲁公开课 - 基础物理课程节选

He could be as hard as a robot, or as smooth as liquid.

VOA: special.2009.07.05

Using a 3D accelerometer, the eLECT analyzes terrain with a 0.2 second window to adjust to how bumpy or smooth your ride is.

ENGADGET

He still moves with an effortless steadiness over the testing terrain, not a bead of sweat on his bald pate or smooth brow, both tanned a rich chestnut.

BBC: Sardinia, land and sea

But it may be stoney or smooth.

BBC: It could get even nastier for Mitt Romney