英语翻译This is John speaking

英语翻译This is John speaking this is john speaking的问句 This is John speaking.Who's that? Hello!__________________________?B:This is John speaking.___ 英语翻译HI,this is Jack speaking.为什么要加speaking? This is John speaking .who is that?A,i am bill B This is Helen speaking. this is tom speaking ( this is Kangkang speaking. Is this Tom speaking? This is she speaking. this is Jack speaking