Section BDirections:In this part there is a short passage fo

Section B
Directions:In this part there is a short passage followed by five questions or incomplete statements.React the passage carefully.Then answer the questions or complete the statements with no more than 10 words Please write your answers on Answer Sheet 2
Did you know that the invention of chewing gum (口香糖) was an accident?People have been chewing gum-like substances since the early times.Some were made from thickened resin(树脂),a substance that comes from plants.Others were made from grains and waxes.But chewing gum,as we know it today,was invented by mistake,in 1870 when Thomas Adams,a photographer,became friends with a Mexican military general,Antonio Lopez de Santa Anna.
After Santa Anna defeated the Texans at the Alamo,he was forced to leave his home country Mexico.Santa Anna stayed with Thomas Adams in New York and introduced him to a gummy substance people in Mexico liked to chew called chicle.Chicle was the milky substance from certain trees that grew in the tropical rain forests in Central America.Adams wanted to use the chicle to invent a cheaper substitute for rubber.He tried to make all sorts of items out of chicle,including toys and rubber boots,but each of his experiments failed.
One day,while he was thinking about his failures,he remembered that people in Mexico chewed chicle.Curious,he put a piece of the chicle into his mouth and began to chew on it.Adams added licorice (甘草) to the chicle and opened the world's first chewing gum factory.
Much like Adams's discovery of chewing gum,the invention of bubble gum was also an accident.In 1928,Walter Diemer,an accountant for the Fleer Gum Company in Philadelphia.stumbled upon the invention while experimenting with new recipes (配方) for chewing gum.Diemer created a gum that was less sticky and more stretchy than regular chewing gum.Diemer learned he could blow bubbles with this new gum.
Accidents or not,chewing gum and bubble gum are two inventions that people across the globe like!
Questions:
76.People were able to acquire thickened resin from__________.
77.In his experiments,Adams originally intended to replace rubber with
78.The phrase "stumbled upon" (Para.4) most probably means________
79.Compared with regular chewing gums,bubble gums were__________
80.The passage is mainly concerned with__________.

76 plants
77chicle
78accident
79less sticky and more stretchy
80how chewing gum is invented