surface of constant total curvature

例句：

1. 1.The surface of the lake is smooth and clear.
   湖的表面光滑而清澈。
2. 2.The surface of the ocean is vast and unforgiving.
   海洋的表面广阔且无情。
3. 3. The surface of the earth is constantly changing due to plate tectonics.
   地球表面的不断变化是由于板块构造活动造成的。