【趣谈英语】咖啡因的那些事-Caffeine Is A Natural Pesticide
英语课
Pre-Listening Vocabulary
caffeine: a drug found in some plants, including coffee seeds and tea leaves
pesticide 1: a substance that keeps insects or harmful materials away from a plant
alert: awake and paying attention
ward 2 off: to keep away something harmful
Caffeine Is A Natural Pesticide
Caffeine wakes us up and helps us stay alert. Many people rely on a caffeine kick a few times a day. In fact, coffee and tea are the most popular beverages 3 in the world, making caffeine the most popular drug. Caffeine is found in the seeds, leaves, and fruit of certain plants. Have you ever wondered why caffeine exists in coffee seeds and tea leaves? Studies have shown that caffeine is a natural pesticide. It gives off a bitter odour to ward off or kill insects that come to feed on it. While caffeine is generally safe for humans, it can be toxic 4 to pets and should be kept away from cats, dogs, and birds.
1 pesticide
n.杀虫剂，农药
- The pesticide was spread over the vegetable plot.菜田里撒上了农药。
- This pesticide is diluted with water and applied directly to the fields.这种杀虫剂用水稀释后直接施用在田里。
2 ward
n.守卫，监护，病房，行政区，由监护人或法院保护的人（尤指儿童）；vt.守护，躲开
- The hospital has a medical ward and a surgical ward.这家医院有内科病房和外科病房。
- During the evening picnic,I'll carry a torch to ward off the bugs.傍晚野餐时，我要点根火把，抵挡蚊虫。