What kinds of people often give drugs to their children? Where in the world do people take drug before going to work? The answers are simple—ordinary people, just about【C1】______. And the drug【C2】______question is caffeine. Scientists estimate that over 70% of the world's population takes caffeine daily.【C3】______drink it in tea and coffee. Children drink in tin Coca Cola and【C4】______soft drinks. It is also found in chocolate.【C5】______, most people in the most places at any time are under the【C6】______of the drug. There have been many scientific investigations【C7】______the exact effects of caffeine. Most people agree that it【C8】______the nervous system and helps the body make efficient use of energy. This is why many people【C9】______Asia drink tea with food and why westerners often end their meals【C10】______a cup of coffee. Because the effect of caffeine is so【C11】______, there have been【C12】______attempts to stop people using it. A U. S. religious group which【C13】______the use of caffeine is generally regarded as eccentric(反常的). But because nearly everybody takes it, the total effect of caffeine【C14】______people is huge. Caffeine is the drug that changed the world. Both tea and coffee were introduced to the West around 300 years ago. The effect of these new drinks was felt【C15】______. In New York, coffee houses were【C16】______with people making plans,【C17】______business and doing deals. And the deals done in the coffee houses were partly responsible【C18】______a rapid increase in American trade. History was moving【C19】______that direction anyway. But the arrival of coffee【C20】______everything up. 【C1】