this is Jack speaking

this is Jack speaking 英语翻译HI,this is Jack speaking.为什么要加speaking? this is sam speaking.are you jack哪有错 -is that Jack speaking 今天就要!This is Jack speaking.Are you Tom?（ this is划线；are you划线 This is Helen speaking. this is tom speaking ( this is Kangkang speaking. Is this Tom speaking? This is she speaking. 英语翻译W:Hello!M:This is Tom speaking.I’d like to speak to jack hello it is jack speaking?yes （ ）