What do you mean when a man sends a message asking what you just sent?

It's because he didn't understand the meaning of the last item, because only if he didn't understand the last item will he ask you what you just sent. Information refers to the objects transmitted and processed through audio, message and communication systems, and generally refers to all the contents spread by human society. People can distinguish different things by obtaining and identifying different information from nature and society, so as to understand and transform the world. In all communication and control systems, information is a common form of communication. 1948, mathematician Shannon pointed out in his paper entitled "Mathematical Theory of Communication": "Information is used to eliminate random uncertainty". The most basic unit of creating everything in the universe is information.