课文内容：

No one can avoid being influenced by advertisements. Much as we may pride ourselves on our good taste, we are no longer free to choose the things we want, for advertising exerts a subtle influence on us. In their efforts to persuade us to buy this or that product, advertisers have made a close study of human nature and have classified all our little weaknesses.

Advertisers discovered years ago that all of us love to get something for nothing. An advertisement which begins with the magic word FREE can rarely go wrong. These days, advertisers not only offer free samples, but free cars, free houses, and free trips round the world as well. They devise hundreds of competitions which will enable us to win huge sums of money. Radio and television have made it possible for advertisers to capture the attention of millions of people in this way.

During a radio programme, a company of biscuit manufacturers once asked listeners to bake biscuits and send them to their factory. They offered to pay $10 a pound for the biggest biscuit baked by a listener. The response to this competition was tremendous. Before long, biscuits of all shapes and sizes began arriving at the factory. One lady brought in a biscuit on a wheelbarrow. It weighed nearly 500 pounds. A little later, a man came along with a biscuit which occupied the whole boot of his car. All the biscuits that were sent were carefully weighed. The largest was 713 pounds. It seemed certain that this would win the prize. But just before the competition closed, a lorry arrived at the factory with a truly colossal biscuit which weighed 2,400 pounds. It had been baked by a college student who had used over 1,000 pounds of flour, 800 pounds of sugar, 200 pounds of fat, and 400 pounds of various other ingredients. It was so heavy that a crane had to be used to remove it from the lorry. The manufacturers had to pay more money than they had anticipated, or they bought the biscuit from the student for $24,000.