Reduction method: It is a method of determining that the rebutted topic is false by assuming that the rebuttable topic is true, thereby extending a clearly absurd conclusion;. By definition, B uses abduction. ['A said, "You see, plums on the roadside trees must be very sweet. " B said, "If it was sweet and was picked away early, how could it be full of fruit trees?', 'A said: "Nuclear power plants are radioactive; therefore they are dirty. " B said "Nature is also radioactive, can it be said that nature is also dirty? " ".', 'A said: "All the defendants are guilty. " B said: "The defendants in civil proceedings are not guilty. ".', 'A said, "If you put 5 pigeons in 2 bird cages, at least 2 of them will be in the same birdcage. " B said, "There is also only one birdcage. ".']