A、Because they may need these books from time to time. B、Because these books are very precious and valuable. C、Because they hope

M: Excuse me, I wonder if you could help me?
W: Of course. How can I be of assistance?            
M: You see, I’m a first-year student here and I missed my orientation. Before I attend my first lecture, I need to finish the reading assignment of my professor and I really don’t know how to locate them in the library.         
W: OK. Let me take a look. It’s really a long list. Maybe the computerized catalog can save you some time.      
M: You mean the computers like this?
W: Yes. You can find the computer terminals on each floor. Let me show you how to use the system.
M: OK. Thank you.         
W: Before you start to search the whereabouts of a book, you need to know at least some accurate information of the book, like the author or the title. First, log in the system with your student ID, then put the information in the box. Press the search button. You can see clearly where the book is now.            
M: I see. So this means the book Introductory Psychology I need is on the second floor of the east wing?      
W: Yes.
M: What does this red-letter word "reserved" mean?         
W: Oh, this means that you can only read the book in the library and you can’t take it out. Usually requirements like this are made by the professor so that all the students can have a chance to read the book.      
M: Yes, of course. I learned that I can keep the book I borrowed for three weeks and before the book is due, I can renew it if necessary. Is it correct?      
W: Yes, but you can only renew once. And then, if you can’t return the book in time, you will pay a fine.
M: OK, I see. Thank you.         
Questions 5 to 8 are based on the conversation you have just heard.
5.Why does the man come to the library?
6.What information must the man provide for logging in the computerized catalog system?
7.What can be learned about the library?     
8.Why do some professors make some books "reserved"?