A history of long and effortless success can be a dreadful handicap, but, if properly handled, itmay become a driving force. When the United States entered just such a glowing period afterthe end of the Second World War, it had a market eight times larger than any competitor,giving its industries unparalleled economies of scale. Its scientists were the world's best, itsworkers the most skilled. America and Americans were prosperous beyond the dreams of theEuropeans and Asians whose economies the war had destroyed.　

It was inevitable that this primacy should have narrowed as other countries grew richer. Justas inevitably, the retreat from predominance proved painful. By the mid-1980s Americans hadfound themselves at a loss over their fading industrial competitiveness. Some huge Americanindustries, such as consumer electronics, had shrunk or vanished in the face of foreigncompetition. By 1987 there was only one American television maker left, Zenith. (Now there isnone: Zenith was bought by South Korea's LG Electronics in July.) Foreign-made cars andtextiles were sweeping into the domestic market. America's machine-tool industry was on theropes. For a while it looked as though the making of semiconductors, which America hadinvented and which sat at the heart of the new computer age, was going to be the nextcasualty.

All of this caused a crisis of confidence. Americans stopped taking prosperity for granted.They began to believe that their way of doing business was failing, and that their incomes wouldtherefore shortly begin to fall as well. The mid-1980s brought one inquiry after another intothe causes of America's industrial decline. Their sometimes sensational findings were filled withwarnings about the growing competition from overseas.

How things have changed! In 1995 the United States can look back on five years of solidgrowth while Japan has been struggling. Few Americans attribute this solely to such obviouscauses as a devalued dollar or the turning of the business cycle. Self-doubt has yielded to blindpride. "American industry has changed its structure, has gone on a diet, has learnt to be morequick-witted," according to Richard Cavanaugh, executive dean of Harvard's Kennedy School ofGovernment. "It makes me proud to be an American just to see how our businesses areimproving their productivity," says Stephen Moore of the Cato Institute, a think-tank inWashington, D.C. And William Sahlman of the Harvard Business School believes that people willlook back on this period as "a golden age of business management in the United States."

51. The U.S. achieved its predominance after World War Ⅱ because________.

[A] it had made painstaking efforts towards this goal

[B] its domestic market was eight times larger than before

[C] the war had destroyed the economies of most potential competitors

[D] the unparalleled size of its workforce had given an impetus to its economy

52. The loss of U.S. predominance in the world economy in the 1980s is manifested in the factthat the American________.

[A] TV industry had withdrawn to its domestic market

[B] semiconductor industry had been taken over by foreign enterprises

[C] machine-tool industry had collapsed after suicidal actions

[D] auto industry had lost part of its domestic market

53. What can be inferred from the passage?

[A] It is human nature to shift between self-doubt and blind pride.

[B] Intense competition may contribute to economic progress.

[C] The revival of the economy depends on international cooperation.

[D] A long history of success may pave the way for further development.

54. The author seems to believe the revival of the US economy in the 1990s can be attributedto the________.

[A] turning of the business cycle

[B] restructuring of industry

[C] improved business management

[D] success in education