例句與造句

1. :" Second countable and Hausdorff are point-set conditions; second countable excludes spaces of higher cardinality such as the long line, while Hausdorff excludes spaces such as " the line with two origins " ( these generalized manifolds are discussed in non-Hausdorff manifolds ) ."
2. It's difficult to find generalized manifold in a sentence. 用generalized manifold造句挺難的