体裁：议论文 话题：历史故事 时间：6分钟
The movies just wouldn't be the same without the warm buttery taste of popcorn.Amazingly，this delicious treat started its life as a corn kernel(玉米粒)—and not from just any corn.Popcorn is a type of sweet corn that was originally grown in Mexico and spread to China，India and elsewhere.It is the only kind of corn that will pop.Today，most of the world's popcorn is grown in the United States.
Every popcorn kernel contains a tiny drop of water，surrounded by soft starch(淀粉)．When the popcorn is heated，the water turns into steam.This puts pressure on the surrounding hard kernel，forcing it to explode.The soft starch increases about 40 times in size as the corn kernel turns itself inside out.
��学或学院里继续深造。
