Have you ever noticed the black and white bars on a book？Do you know what they are used for？

They are barcodes used in most products．If you go to a supermarket，you can see almost every product with a barcode on it．（60）___，such as name and production date．It's an easy and convenient way to keep track of the products．（61）___．

The first use of a barcode in a supermarket checkout system was on a pack of American Wrigley Company chewing gum in 1974．Besides supermarkets，barcodes are needed everywhere：For renting cars，for luggage checks on a plane，for parcels （包裹） you send．People can enter stadiums，cinemas and theaters by holding certain types of barcodes．（62）___．

If you find these barcode things boring，a barcode building might be more up your street．In St Petersburg，Russia，there is a building designed like a barcode．It looks strange，but it's actually a shopping mall．There are games too．Barcode Monsters is a mobile phone game．（63）___．

A．You have to scan barcodes and find the monsters

B．Just scan the bars with a barcode reader and everything is clear

C．You can buy an iPhone to play the game

D．Life would be rather difficult without barcodes

E．Barcodes contain information about the products．