1. Flatness can be determined by covering a surface with an optically flat glass. 用一光学平面玻璃覆盖一个表面，可以测量平整度。
2. Thomas Hudson looked out at the flatness of the blue sea and the darker blue of the Gulf. 托马斯·赫德森呆望着湛蓝的海面，海面水平如镜。在海湾那儿，都是深蓝一片了。
3. The control of thin strip and foil flatness, or shape, inevitably requires some degree of modelling. 薄带材和箔材的平直度或板形控制必然要求一定程度的模型化。
英英解释
n.
1. the property of having two dimensions
2. a want of animation or brilliance
3. a deficiency in flavor
4. the property of having little or no contrast; lacking highlights or gloss
5. inactivity; showing an unusual lack of energy
