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
The surface-to-surface missiles were fired from the west of the capital.
从首都西部发射了多枚地对地导弹。
《柯林斯英汉双解大词典》
3
If the water table intersect the land surface, groundwater will flow out onto the surface at springs, whether to be collected there or to subsequently flow farther along a drainage.