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Chewing gum(口香糖) may be one of your favorite sweets. But do you know how it was invented? It was invented by American scientist Thomas Adams. ________, he invented it totally by mistake. It was 1869. Earlier that year, one of Adams friends showed ________ an interesting kind of sap(树汁). The sap was very elastic(有弹性的). Ancient people in Central America liked to chew on it for ________. Adams was interested in the sap. He wanted to use it to ________ some new products.

Adams, however, failed to create the products he wanted. He felt ________ and angry and happened to chew on the sap. To his ________, the sap tasted great. Adams then ________ his own flavors(调味) to the sap and started selling it. Later in 1869, he opened a factory to produce this delicious sweet.

In 1888, Adams gave a name to the ________: chewing gum. The sweet could be bought by vending machines(自动售货机) at subway stations all over New York City. Over the years, new flavors have been developed. Now, chewing gum is ________ among both children and adults. However, few people know this was all started by an American scientist from a ________.