“非”在逻辑中表示否定的含义,在讲道理的过程中,“非”很重要,一个命题p的非就是命题p的否定,记作■p。在实际教学中,“非”容易出错误,中学阶段常遇到的是对简单命题、含联结词“或”与“且”形式的复合命题、含全称量词()与存在量词(■)等命题的否定,难度均不大,学生基本可以掌握。下面,笔者结合例题介绍自己对“非”容易出问题的假言命题的否定的理解。 “Non ” denies the meaning of logic in the logic, in the process of reasoning, “non ” is very important, a proposition p is the negation of the proposition p, denoted as ■ p. In actual teaching, “non ” is prone to error, often encountered in high school stage is a simple proposition, with conjunctions “or ” and “and ” in the form of composite proposition, And the existence of quantifiers (■) and other propositions of the negative, the difficulty is not large, students can master. The following, the author combines examples to introduce their own “non ” easy to question the hypothesis of the negative understanding.