Since the method returns input unchanged if there isn't any match, You can utilize the Object.ReferenceEquals system to determine whether the method has produced any replacements towards the enter string.?�が?�詞?�し?�使?�れ?�場?�、物?�人?�元?�の位置?�状?�か?�新?�い?�の?�交?�さ?�る?�と?�