听力原文： During the last few years, there has been an enormous increase in the number of shops, stores and supermarkets which provide facilities for self-service. Their general purpose is to provide goods of every description attractively and cleanly and in perfect condition, so that the customer can serve herself, and then pay for the goods with. the minimum of delay. The organizers of a self-service store have their difficulties. They must display a great number of goods in a minimum space without covering up anything. They must deal with perishable foodstuffs requiring different ranges of temperature and they must arrange a speedy flow of customers past the cash registers without overtaxing the operators. For the purposes of display, many devices are used such as long lengths of adjustable shelves to take various sizes of packs, rotating circular shelves, islands of display stands, racks for tubed foods, and multi-tiered mobile stalls. Perishable foodstuffs and quick frozen fruit, vegetables and meat are kept in refrigerated self-service cabinets, which keep goods at the required temperatures. These are at zero Fahrenheit for frozen food, 28-32 degrees for meat and fish, and 40-50 degrees for dairy produce and provisions. Some of the advantages of self-service seem to be that there is no waiting to be served there is a wide variety of choice, and it is claimed that prepacked meat and vegetables are hygienic. Shopping is said to be more 'streamlined' and more economical. Nevertheless many people still prefer to be served by a small shopkeeper who knows them personally and will deliver goods to their homes. (33)