1. The first is about prepositional classification. In general logic, proposition consists of two categories, the simple proposition and the compound proposition. 一论命题的分类：在普通逻辑中，命题分成简单命题和复合命题两类，简单命题分成直言命题和关系命题两种。
2. A proposition on which another proposition depends; the antecedent of a conditional proposition. 前提为另外一命题所依赖的命题；
3. proposition system of expressing scientific knowledge——atomic proposition, molecularproposition, and generalized proposition; 表达科学知识的命题系统——原子命题、分子命题和概括命题；
4. A proposition derived by negating and permuting the terms of another, equivalent proposition; for example, All not-Y is not-X is the contrapositive of All X is Y. 质位变换命题由否定和置换另一等价命题的项而得到的命题；例如，“所有的非y是非x”是“所有的x是y”的质位变换命题。
5. A proposition derived by negating and permuting the terms of another, equivalent proposition; for example, All not-Y is not-X is the contrapositive of All X is Y. 质位变换命题由否定和置换另一等价命题的项而得到的命题；例如，“所有的非y是非x”是“所有的x是y”的质位变换命题。
