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(reading) the Analects of Confucius to a dogwasting one's breath (trying to explain something)