填空题. A. manufacture B. saw C. travels D. relieving E. extraction F. condensed G. journeys H. handled I. purified J. subjected to K. treated L. as M. when N. refreshing O. assigned The ancient Aztecs venerated the cacao tree and used its beans as a form of currency. They 1 the tree as a source of strength and wealth and 2 their god Quetzalcoatl its guardian. The Aztecs discovered that by crushing the beans into a paste and adding spices, they could make a 3 and nourishing drink. This drink would have been very bitter, unlike our chocolate drinks today. 16th century European explorers brought the drink back from their 4 , added sweeter flavorings, and soon it was popular as an expensive luxury. In the 1800s, solid chocolate became popular, with the invention of molding processes. Mechanical grinders crushed cocoa beans to a fine powder that could be heated and poured into molds, forming shapes 5 it cooled. Dutchman Coenrad Van Houten perfected the 6 of cocoa butter from cocoa beans in 1825. The beans are crushed to a paste, which is 7 very high pressure, forming chocolate liquor and cocoa butter. The extracted butter is smoothed and 8 to remove any odors. In the 1880s, Rudolphe Lindt of Switzerland started adding extra cocoa butter during chocolate manufacture, to make it smoother and glossier. Cocoa butter melts at around 97℉, which is human body temperature. That's why chocolate melts in the mouth. In 1875, Swiss Daniel Peter perfected the 9 of milk chocolate, which is sweeter and smoother than dark chocolate. Nestlé's recently-invented 10 milk was easy to mix with cocoa paste, unlike liquid milk. Cadbury's "Dairy Milk", first developed in 1905, is the UK's most popular chocolate bar. Milk chocolate is now the world's best-selling variety.