21. The computer-readable recording medium according to claim 10 , wherein, in the step (c), for each of the combinations, one of a degree of word coverage and a degree of word matching for only the word serving as the argument between the predicate-argument structure of the first text and the predicate-argument structure of the second text is obtained, as the feature amount, based on a word other than a word indicating the type of argument of a predicate in the predicate-argument structure.
21. The computer-readable recording medium according to claim 10 , wherein, in the step (c), for each of the combinations, one of a degree of word coverage and a degree of word matching for only the word serving as the argument between the predicate-argument structure of the first text and the predicate-argument structure of the second text is obtained, as the feature amount, based on a word other than a word indicating the type of argument of a predicate in the predicate-argument structure. 24. The computer-readable recording medium according to claim 21 , wherein, in the step (c), a weight is added to the feature amount based on data obtained through machine learning, when obtaining the feature amount.