百日の説法屁一つひゃくにちのせっぽうへひとつ慣用句ことわざ未分類one blunder rendering a long period of effort uselessone fart in a hundred days of sermons
犬に論語いぬにろんご慣用句ことわざ未分類(reading) the Analects of Confucius to a dogwasting one's breath (trying to explain something)