你好！面对面时可以说 Excuse me，who are you？或者 Who are you，please？电话里说 Who is that？（那是谁，就是问”电话那边是谁“）
文雅一点的说法：May I know who i am speaking with?
who's speaking？
who'scalling?1.你是哪位？（接电话者问对方）2.谁打来的电话？（说话者问正在接电话者）
