Unit 4,Then and now,A. Lets learn,There are many books in it. We can read books in it. What is it,Its a _,library,There are teachers in it. They often work there. And you often hand in （上交）your homework there. What is it,Its a _,teachers office,There are many computers here. You can learn how to use computers.What is it,Its a _,computer room,There are two blackboards. There are many desks and chairs in it. What is it,Its a _,classroom,What
