If the glass were kept hot enough, it would flow over the molten tin until the top surface was also flat, horizontal and perfectly parallel to the bottom surface.

如果玻璃保持足够的温度，它就会在熔化的锡中流动，直到顶部表面也变得平整、水平，与底部表面完全平行。

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Its carved underside shapes the lobby below, while its top surface is the floor plate of the exhibition space.

凹陷的下方雕刻形成了大堂的下方，而凹陷的上表面则是展览空间的底板。

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So, that means you have to figure out what's the bottom surface of your solid, and what's the top surface of your solid?

这意味着你必须指出,立体图形的底部的曲面，和立体图形的顶部曲面？

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The very top of the wire drawing represents the only part of the ocean landscape that can be seen on the surface of the water: It is Bouvet Island, one of the most isolated islands in the world.

VOA: special.2009.05.06

The one that's on the top here is called ligand-gated ion channel and an ion channel is a protein that sits in the surface of a cell.

最上面的这个叫作配体门控离子通道,离子通道是一类位于细胞表面的蛋白

耶鲁公开课 - 生物医学工程探索课程节选

What at first glance appears to be a jumble of boulders was probably a workshop where expert stonecutters practiced their trade. (One chunk of granite has been carved into almost-finished steps.) Another large stone, known as Serpent Rock, has snakes etched into its top surface.

BBC: What most people miss at Machu Picchu

Satellites have long been used to track ice extent (area), but calculating the thickness of the marine floes requires the overflying spacecraft to gauge the difference between the top of the ice surface and the top of the water - a relatively simple calculation then gives the overall volume.

BBC: Launch success for Esa's Cryosat-2 ice mission

The device has some of the same features as a table-top device called Surface which is produced by Microsoft.

ECONOMIST: Innovation