People in different countries use different types of money: yuan in China, pesos in Mexico, pounds in the United Kingdom, (51) in the United States, Australia and New Zealand. They may use different currencies, but these countries, and probably all countries, still have one thing (52) : Germs on the banknotes. Scientists have been studying the germs on money for well over 2, 100 years. (53) the turn of the 20th century, some researchers began to suspect that germs living on money could spread disease. Most studies of germy money have looked at the germs on the currency within one country. In a new study, Frank Vriesekoop and other researchers compared the germ (54) found on bills of different countries. Vriesekoop is a microbiologist at the University of Ballarat in Australia. He led the study, which (55) the germ populations found on money gathered from 10 nations. The scientists studied 1, 280 banknotes (56) ; all came from places where people buy food, like supermarkets, street vendors and cafes, because those businesses often (57) cash. Overall, the Australian dollars hosted the fewest live bacteria—-no more than 10 per square centimeter. Chinese yuan had the most—about 100 per square centimeter. Most of the germs on money probably would not (58) harm. What we call "paper money" usually isn't made (59) paper. The U. S. dollar, for example, is printed on fabric that is mostly cotton Different countries may use different materials to print their money. Some of the currencies studied by Vriesekoop and his team, such as the American dollar, were made from cotton. (60) were made from polymers. The three currencies with (61) numbers of bacteria were all printed on polymers. They included the Australian dollar, the New Zealand dollar and some Mexican pesos. The other currencies were printed on fabric made mostly of cotton. Fewer germs lived on the polymer notes. This connection suggests (62) germs have a harder time staying alive on polymer surfaces. Scientists need to do more studies to understand how germs live on money and (63) or not we need to be concerned. Vriesekoop is now starting a study that will compare the amounts of time bacteria can stay alive on different types of bills. Whatever Vriesekoop finds, the fact (64) : Paper money harbors germs. We should wash our hands after touching it; (65) , you never know where your money's been. Or what's living on it.
单选题
A. dollars B. money C. bucks D. corns
【正确答案】
A
【答案解析】冒号后面说的是各国使用钱币的名称：“yuan in China，pesos in Mexico，pounds in the United Kingdom，...”，因此这里填入的词应该是特指美国具体的纸币dollars。
单选题
A. in different B. in places C. in common D. in return
【正确答案】
C
【答案解析】本题的句子说的是各国钱币都有共同点，就是纸币上有细菌，因此应该选in common。
单选题
A. In B. At C. With D. From
【正确答案】
B
【答案解析】at the turn of...为固定搭配，意为“在...之时、之际”，文中的意思为“在二十世纪初期”，故选B。