Teeth have a hard surface layer called enamel.

牙齿有一层叫做釉质的坚硬表层。

《牛津词典》

Most Roman pottery is light and smooth to touch and very tough, although, like all pottery, it shatters if dropped on a hard surface.

大多数罗马陶器轻巧而光滑，摸起来很硬，但像所有的陶器一样，如果掉在坚硬的物质上就会碎裂。

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Understanding polygonal subdivision and how it relates to hard surface modelling.

了解多边形细分及其与硬表面建模的关系。

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The fluoride mixes with enamel, the hard surface on teeth, to help prevent holes, or cavities,from forming.

VOA: special.2009.03.11

The result is a container with a hard surface that will last for many years.

VOA: special.2009.09.14

Find a hard surface like a chair and rest your body on it.

VOA: special.2009.08.11

But McNamara's men made light of the freezing temperatures and hard surface to deliver an emphatic display.

BBC: Bradford Bulls 41-22 Castleford Tigers

The beige-granite counter is a hard surface for craft projects, and a cupboard holds paints and crayons.

WSJ: Kitchen Islands Get More Built-In Appliances, Storage and Features

Prosecutors charged Woodward with first-degree murder, accusing her of shaking Matthew and slamming his head against a hard surface.

CNN: Cross-examination of nanny called 'minefield' for prosecution