The shell is smooth on the inside.

贝壳内壁光滑。

《牛津词典》

The coat was smooth and shiny inside like her sister Sylvia's blouses.

外套里面光滑发亮，就像她姐姐西尔维亚的衬衫。

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Video available on the team's web site shows the team exploring inside a wooden structure embedded in a sort of ice cave. The wooden walls of one compartment are smooth and curved.

探险队网站上提供的录像显示探险队在一个冰洞里考察一个镶嵌其中的木质结构，一个隔间里的木墙壁光滑有曲线。

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So far, I have found it incredibly smooth to drive, powerful and roomy inside.

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Inside, the tunnel was cool and dark, about thirty feet high, with a smooth ceiling, faintly lit by work lights along the edges.

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