You (to understand) what he( to talk) about? Where ( to be) John? - He( to do) his homework/ He (to do)it for three hours

1. Do you understand what he is talking about? 2. Where is John? - He is doing his homework. He has been doing it for three hours. 3. I can not give you the book, I am still reading.- Are you? How long have you been reading it? 4. What are you going to do tonight? I am going to study for my exams. But I will have finished by 8 o\'clock, I hope. - Good. Let\'s go to the cinema then. The film starts at 8.30.