Question 25 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.

25. What have generations of American politicians argued for?

解析：C。录音末尾处提到，在美国历史上，一代又一代的政治家都赞成美国货币实行金本位制，题目中的generations of politicians和C项的A gold standard for American currency均为录音中的原词复现，故正确答案为C。

错项排除：A项利用录音原词dollar value进行干扰，录音末尾处提到，就目前而言，美元钞票的价值等同于其钞票面值，除此之外再无额外价值，这与历代美国政治家的观点无关，故A项排除。B项利用录音原词government securities进行干扰，但录音最后一句说的是，钞票价值的唯一其他担保，就是美联储以国债为抵押对美元进行信用担保，不是说美国政治家都赞成政府债券的发行，B项属于细节拼凑，故错误。D项利用录音原词steady进行干扰，但录音中说的是，政府始终稳定保持着约20亿张流通钞票的供应，appreciation（升值）一词在录音中无依据，故可排除D项。