Thus when I demonstrate any proposition concerning triangles it is to be supposed that I have in view the universal Idea of a triangle;

就如我在证明关于三角形的任何命题时，人虽然假定我着眼于一个普遍的三角形观念；

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Thus when I demonstrate any proposition concerning triangles it is to be supposed that I have in view the universal Idea of a triangle;

就如我在证明关于三角形的任何命题时，人虽然假定我着眼于一个普遍的三角形观念；

youdao