Both of these formulas basically relate work on a curve with what happens to the curl on the surface that is enclosed by this curve, that is bounded by this curve.
基本上，这两个公式把沿曲线的功，和被曲线包围的曲面上的旋度，联系起来了，曲面是以该曲线为边界的。
2
What it says on each small flat piece — it says that the line integral along say, for example, this curve is equal to the flux of a curl through this tiny piece of surface.