Caffeine (咖啡因), a chemical typically found in coffee, has caused a lot of attention because it is one of the few drugs (毒品) that show up regularly in our food supply. You probably (use) caffeine since childhood. Caffeine (be) in your first Coke. If you ever enjoyed a chocolate bar, you ate caffeine. Soft drinks are the major source (来源) of caffeine for most children and even some adults. (recent), caffeine has found its way into orange, apple, and other drinks.
Small amounts (数量) of caffeine—a cup two of coffee a day—seem safe for most people. ,some people have trouble with even small amount. One cup of coffee in the late afternoon or evening will cause them (stay) awake almost all night. Larger amounts of caffeine can cause a problem (call) caffeinism. You get very nervous and you can't sleep.
It is possible caffeine may cause birth defects (缺陷) in humans, too. One study showed that (woman) who drank a lot of coffee, like eight or more cups per day, while they were pregnant (怀孕的) were more likely to have children birth defects.
