题目内容：

Did you notice the number on the book in a library? That number is part of the system used by libraries to organize their collections of books. And it’s used in many countries. The number on each book tells you exactly what kind of book it is. This system is also useful for knowing where to go in the library to find a book.

In this system, there are ten large groups of books. Each of these groups has its own number, such as 100, 200, etc. So, for example, any books about language will have a number 400. On the other hand, any books about history will have a number 900. So, a number in the hundreds place tells you what general group a book is in. If you find a book that has a number in the 500s, you know it is a book about science.

However, science is a big group, so the tens place is used to make a more detailed set of science books. For example, math books are included in the group of science books. Math books all have numbers between 510 and 519. Books about the history of Africa have numbers between 960 and 969.

The system uses the ones place to give a more exact limit for the subject of a book. A book on the history of South Africa will have the number 968.

As you can see, it is a simple system to use as long as you understand what the numbers mean. With this system, the library can keep its books well organized, and people can easily find the book that they want.

1.The reading is about       .

   A. libraries

B. working in a library

   C. how numbers are organized

D. how books are organized in libraries

2.The number system is NOT used to       .

   A. find where a book is 

B. tell you the title of a book

   C. tell you what kind of book a book is        

D. organize the collections of books in libraries

3.According to the reading, which sentence is TRUE?

   A. The number on a book can’t be bigger than 900.

   B. There are ten big groups for books in this system.

   C. History books can have any number between 500 and 900.

   D. This system uses both numbers and letters for some books.

4.A book about math can be found in the same group of books as       .

   A. reference books   B. school books     C. science books   D. art books

5.Which two numbers would indicate a book about language and a book about science?

   A. 439 and 493       B. 439 and 568      C. 530 and 560     D. 563 and 436