hello!who is that speaking?

hello!who is that speaking? hello who is that speaking什么意思 Hello,is that Mr.Black speaking?Yes,who's that? -Hello, who’s that speaking? Hello.Is that Mary speaking? Who is that speaking? ---hello,is this Mr.liu speaking?----(yes,who is that?that怎么 a:hello.who's that?b:（）.（）is mike speaking.I have a fever.I Hello,is that Mary?Sorry,___Lusy speaking. --- Hello,is that Jim ___?---Speaking. Hello!Who's speaking? Hi!Who's that speaking?----Hello!_____ Tom!