Question 24 is based on the recording you have just heard.

听力原文

    Virtually every American can recognize a dollar bill at a mere glance. Many can identify it by its sound or texture. (22) [But few people indeed can accurately describe the world’s most powerful, important currency.] 

    The American dollar bill is colored with black ink on one side and green on the other; (23) [the exact composition of the paper and ink is a closely guarded government secret.] Despite its weighty importance, the dollar bill actually weighs little. It requires nearly 500 bills to tip the scales at pound. Not only is the dollar bill lightweight, but it also has a brief lifespan. Few dollar bills survive longer than 18 months.

    The word “dollar” is taken from the German word “thaler”, the name for the world’s most important currency in the 16th century. The thaler was a silver coin first minted in 1518 under the reign of Charles V, Emperor of Germany.

    The concept of paper money is a relatively recent innovation in the history of American currency. When the Constitution was signed, people had little regard for paper money because of its steadily decreasing value during the colonial era. (24) [Because of this lack of faith, the new American government minted only coins for common currency.] Interest-bearing bank notes were issued at the same time, but their purpose was limited to providing money for urgent government crises, such as American involvement in the War of 1812. The first non-interest bearing paper currency was authorized by Congress in 1862 at the height of the Civil War. At this point, citizens’ old fears of devalued paper currency had calmed, and the dollar bill was born. The new green-colored paper money quickly earned the nickname “greenback”.

    Today, the American dollar bill is a product of the Federal Reserve, and is issued from the 12 Federal Reserve banks around the United States. The government keeps a steady supply of approximately 2 billion bills in circulation at all times.

    Controversy continues to surround the true value of the dollar bill. (25) [American history has seen generations of politicians argue in favor of a gold standard for American currency.] However, for the present, the American dollar bill holds the value that is printed on it, and little more. The only other guarantee on the bill is a Federal Reserve pledge as confirmation in the form of government securities.

24. Why did the new American government mint only coins for common currency?

解析：A。根据选项关键词paper money、circulation、value和counterfeit，推测本题可能与货币的流通、伪造或币值有关。录音中说到，由于对纸币缺乏信心，新成立的美国政府只铸造硬币作为流通货币。A项中的paper money为原词复现，little faith是对录音中lack of faith的同义替换，故正确答案为A。

错项排除：B项利用录音中的circulation进行干扰，录音后半部分说到，政府始终稳定保持着约20亿张流通钞票的供应，但这说的是美钞现在的流通情况，与美国政府刚成立时只铸造硬币作为流通货币无关，故B项错误。C项利用value进行干扰，录音中说到，在签署美国宪法时，纸币的价值在不断下跌（decreasing），但这并不意味着硬币的价值会上涨，C项内容属于过度推断，故错误。D项中的counterfeit在录音中没有依据，故排除。