this is a conversation between you and you friend for eg. - rohan.
You- hey rohan! look at this book. What do you think whose book this might be?
rohan - see here, there is a stamp of our school's library this means someone has been careless about the book.
you - yes, now what should we do?
rohan - we should ask our class , may be they could provide any help.
you - that's right but English lecture is going to start , so it would be better if we submit the book to the library teacher, he would be able to find about the student from the library records.
rohan - yes you are right, hurry up! or we will be delayed.