例句與造句

1. These are doubly ruled surfaces of negative Gaussian curvature.
2. This illustrates the doubly ruled nature of this surface.
3. The hyperbolic paraboloid and the hyperboloid of one sheet are doubly ruled surfaces.
4. The hyperbolic paraboloid is a doubly ruled surface : it contains two families of mutually skew lines.
5. The properties of being ruled or doubly ruled are preserved by projective maps, and therefore are concepts of projective geometry.
6. It's difficult to find doubly ruled in a sentence. 用doubly ruled造句挺難的
7. A surface is "'doubly ruled "'if through every one of its points there are " two " distinct lines that lie on the surface.