When we are having a conversation, the response/comment from the other person to our last sentence acknowledges that the other person heard our sentence. For instance, if person A and B are having a conversation and it goes like this A - Do you want a beer? B - Sure (at this point A knows B heard his sentence) But B needs A to say something to know that he heard his response. Since there is always one last sentence for which there won't be an answer, how do people know that the last sentence was heard? Anyone willing to think about this with me? It's strange how it works even though this limitation exists.