flatness of the response

例句：

1. 1. Thefloor is very flat and easy to clean.
   地板非常平坦，容易清洁。
2. 2. The car's suspension system needs to be checkedfor flatness.
   汽车的悬挂系统需要检查是否平整。
3. 3. The surface of the tableis too flat, it feels uncomfortable.
   桌子的表面太平了，感觉不舒服。