Câu hỏi:

Why do people like to chew gum? Some people say they like the taste. ____24____ say they can think better if they chew gum. Some people chew it when they have some boring work to do. Others chew gum when they are nervous.

Gum is a ____25____ of things. For many years gum companies made gum from chicle. Chicle is a natural gum from a tree in Mexico and Central America. Now companies use plastic and rubber made from petroleum instead of chicle.

Gum must be soft ____26____ you can chew it. A softener keeps it soft. The gum company makes the softener from vegetable oil. A sweetener makes the gum sweet. The sweetener is usually sugar. Then the company adds the flavor.

Thomas Adams made the first gum from chicle in 1836. ____27____, chewing gum was not new. The Greeks chewed gum from a tree over 2,000 years ago. Mayan Indians in Mexico chewed chicle. Indians in the Northeastern United States taught Europeans to chew gum from a tree there.

 People first made bubble gum in 1928. Children like to ____28____ bubble with bubble gum. Some university students do too

Some people say they like the taste. ____24____ say they can think better if they chew gum