flat satin

例句：

1. 1. The floor is very flat and easy to clean.
   地板非常平坦，易于清洁。
2. 2. The car was parked on a flat surface.
   汽车停在一个平坦的表面。
3. 3. The roof of the house is flat and does not slope.
   房子的屋顶是平坦的，没有倾斜。