# 2022 Tianjin Community test line test preparation guide, the proposition of “true or false words” question

Necessity reasoning is the key question type of this part of logic judgment, and examinees are often troubled by some questions similar to “true or false words” in the process of solving the question.In this, public education for the examination of the “true and false words” problem of the topic analysis, sorting out some questions involving categorical propositions related to the test of the “true and false words” problem, can help candidates better solve such problems, for everyone’s reference.To solve this kind of problem, we should first make clear what contradiction is.In logical relation, contradiction refers to the description of the same thing about which two propositions must always be true and one false.For example, taking life as the subject, life and death constitute a contradictory relationship. They constitute the whole collection of life and meet the requirement of “one must be true and one must be false”.So, in addition to understand the basic meaning of contradiction, for the test often test about categorical proposition contradiction also want to master and use proficiently, namely: “all is” contradiction is “some non”, “some is” contradiction is “all non”, “some is” contradiction is “some non”.On this basis, it can help us solve this kind of problem. Let’s take a question as an example: Example A, B, C and D respectively express their views on the items in the four boxes.A: Some boxes have no sugar in them.B: There is sugar in all the boxes.C says: There are no peanuts in the second box;Ding said, There are cigarettes in the third box.If only one of the four is telling the truth, which of the following must be true?A. There is sugar in all four boxes B. There is no sugar in all four boxes C. There are peanuts in the second box D.The third box contains cigarette C.According to the characteristics of the form of the question, it can be determined as the “true and false words” problem, and the method of “finding contradictions” is preferred to solve it.According to the basic idea of “a search, two around, three back”, find the contradiction in the problem.Known armour is “some”, second is “all”, known as the contradictory relations, both will be a true one false, the other two then bypass the contradictory relationship between observation conditions, by the “only one of the four” knowable, C and d are all false, in turn, launched in the second box with peanut, the third box without cigarettes, so item to C.Public education believe everyone through this topic has been involving categorical preposition “true and false words” problem, we all want to practice during the test, truly mastering such a problem, keep in mind the proposition of the contradictory relations, flexible use of “three back to a find, second round,” the method to solve the problem, no longer like a headless chicken.I hope today’s carding content is helpful for everyone to prepare for the exam!