dialogue: W: We should buy a good guide-book and study it before our trip to the United States. M: We could, but they are too expensive. Why not borrow one from the library?
question: What does the man mean?
choice: It might not be necessary to buy a guide-book. He doesn't mind the cost of a guide-book. They can get a guide-book in the United States.
answer: It might not be necessary to buy a guide-book.