题目内容：

One hundred and thirteen million Americans have at least one bank-issued credit card. They give their owners automatic credit in stores, restaurants, and hotels, at home, across the country, and even abroad, and they make many banking services available as well. More and more of these credit cards can be read automatically, making it possible to withdraw or deposit money in scattered locations, whether or not the local branch bank is open. For many of us the “cashless society” is not on the horizon---it’s already here.

While computer offer these conveniences to consumers, they have many advantages for sellers too. Electronic cash registers can do much more than simply ring up sales. They can keep a wide range of records, including who sold what, when and to whom. This information allows businessmen to keep track of their list of goods by showing which items are being sold and how far they are moving. Decisions to reorder or return goods to suppliers can then be made. At the same time these computers record which hours are busiest and which employees are the most efficient, allowing personnel and staffing assignments to be made accordingly. And they also identify preferred customer for promotional campaigns. Computers are relied on by manufacturers for similar reasons. Computer analyzed marketing reports can help to decide which products to emphasize now, which to develop for the future and which to drop. Computers keep track of goods in stock, of raw materials on hand, and even of the production process itself.

Numerous other commercial enterprises, from theaters to magazine publishers, from gas and electric utilities to milk processors, bring better and more efficient services to consumers through the use of computers.

49.According to the passage, the credit card enables its owner to     .

A. withdraw as much money from the bank as he wishes

B. obtain more convenient services than other people do

C. enjoy great trust from the storekeeper

D. cash money where he wished to

50. From the last sentence of the first paragraph we learn that     .

A. in the future all the Americans will use credit cads

B. credit cards are mainly used in the United States today

C. nowadays many Americans do not pay in cash

D. it is now more convenient to use credit cards than before

51. The phrase“ring up sales”most probably means     .

A. make an order of goods            B. record sales on a cash register

C. call the sales manager             D. keep track of the goods in stock