usefulnessKK [ˋjusfəlnəs] /ˈjusfəlnəs/發音名詞1用處、實用性、有用The new software proved its usefulness within the first week.這個新軟體在第一週就證明了它的實用性。2效用、價值The old printer has outlived its usefulness and should be replaced.這台舊印表機已經沒有利用價值了,應該換掉。