smoothing problem

例句：

1. 1.The surface of the glass is very smooth.
   玻璃的表面非常光滑。
2. 2. The road was smooth enoughto drive on without any problems.
   这条路很平，开车时没有任何问题。
3. 3. The paint jobon the car looks very smooth.
   汽车上的油漆看起来非常平滑。