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。
2
When pouring molten glass onto the molten tin, the underside of the glass would also be perfectly flat.
当把玻璃液倒在锡液上时，玻璃的底面也会变得完全平整。
3
IN TIN of digital elevation model constructed from contours, flat areas which are made up of flat triangles can not reflect the real shape of the surface, so that they need be corrected properly.