听力原文：Anchor: Imagine the U.S. economy blasting forward, technology changing the way we work and live, a nation obsessed with every little move on the stock market. Sound familiar? Well, it was the actual America at the end of the 1920s. Then 70 years ago today, October 29, 1929, the nightmare on Wall Street. For 'The Events of the Century' tonight, Steven Buffer on the day forever known as 'Black Tuesday'. Steven Butler: Tonight, the stock market crash of 1929. The famous words, the Crash 1929. Overnight, it was like bombs fell. It is often identified as one of the most significant events of the 20th century, the day the stock market lost 30 billion dollars' paper value in a few hours and, as popular wisdom has always told us, plunged the nation into the Great Depression. But popular wisdom about the crash is somewhat misleading, the economy was in depression long before the bottom dropped out of the market. The crash wasn't the only signal that something was terribly wrong it was simply the loudest. An economist: Beneath the surface (erm) there were people who were not worrying in the 20s, the whole frame. of economy was essentially in depression throughout the 20s. Steven Butler: To better understand what forced the economy into such a dark period and the crash's role in that, a few things about the times. It was the first decade in which more people lived in cities than in the countryside, the decade of the automobile, and the radio, and tabloid, and jazz. It was a decade of rampant speculation. It seems that almost everybody was on the stock. And all of these are dependent on mass consumption. An economist: The mass sale of automobiles, in addition, you have radio and household appliances. These, in order to keep the economy going, had to be sold to the masses of people. Steven Butler: Which meant breaking down the traditional American value of saving for a rainy day. Advertising came of age in the 1920s. People were persuaded to abandon their frugal ways and spend money now. And while there were modest increases in the income for the middle classes in 1920s, they were not enough. The economy was booming, but the rich were keeping most of the profits. It means that the buying power was not defused throughout the economy. At a time when unions were either rare or weak, management's hold on wages went unchanged. For a time the flaw in the economy was hidden. An economist: The stopgap that was discovered was, 'I can buy it on credit.' The very word 'credit' starts to be used in the 1920s in a way that's almost opposite to what it really means it means debt. Steven Butler: And the debt mounted and mounted to where it became increasingly impossible to keep up spending. Industry was overproducing, profits were shrinking, the national mood changed. By October 29, 1929, millions of investors started to panic. The stock market went into a free fall. What followed was a period of sustained misery. In the end, the Great Depression lasted another ten years and when America emerged it was a very different place. The growth of organized labor had helped to spread the prosperity more evenly and the commitment of a balanced consumer-driven economy was now complete. But for those who remember the worst trading day in history, the crash of 1929 continues to cast a shadow across the rest of the 20th century. ?You will hear a news report in which the anchor will introduce you to a reporter who will look back at the stock market crash of 1929. ?For each question 28--30, mark one letter (A, B or C) for the correct answer. ?You will hear the recording twice. From the recording we can learn that the crash of 1929 happened on a ______.