共用题干 Cerms(细菌) on BanknotesPeople in different countries use different types of money:yuan in China,pesos in Mexico,pounds in the United Kingdom,dollars in the United States,Australia and New Zealand.They may use different cur-rencies,but these countries,and probably all countries,still have one thing in ________(51):germs on the banknotes.Scientists have been studying the germs on money for well over 100 years.At the turn of the 20th ______(52),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_________(53)one country. In a new study,Frank Vriesekoop and other researchers compared the germ populations found on bills of dif-ferent ________(54)Vriesekoop is a microbiologist at the University of Ballarat in Australia.He led the study,which corn-pared the germ populations found on money _______(55)from 10 nations.The scientists studied 1,280 banknotes in total;all came from places where people buy food,like supermarkets,street vendors andcafes,________ (56)those businesses often rely on cash.Overall,the Australian dollars hosted the fewest live bacteria一no more than 10 per square centimeter. Chinese yuan had the________(57)一about 100 per square centimeter. Most of the germs on money probably would not cause harm.What we call "paper money"________(58)isn'tmade from paper. The U.S.dollar,for example,is printed on fabric that is mostly cotton.Different countries may use different________(59)to print their money. Some of the currencies studied by Vriesekoop and his team,such as the American dollar,were made from cotton.Others were made from polymers.The three_______(60)with the lowest numbers of bacteria were all printed on polymers.They included the Australian dollar,the New Zealand dollar and some Mexican pesos.The_________(61)currencies were printed on fabric made mostly of cotton.Fewer germs lived on the polymer notes.This_______(62)suggests that germs have a harder time staying alive on polymersurfaces.Scientists need to do more studies to understand _________(63)germs live on money一andwhether or not we need to be concerned.Vriesekoop is now starting a study that will______(64)the amounts of time bacteria can stay alive on different types of bills.Whatever Vriesekoop finds,the fact remains:Paper money_________(65)germs.We should wash our hands after touching it.After all,you never know where your money's been.Or what's living on it. _________(51)
A.doubt B.danger C.common D.advance正确答案C
