Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
pill – n. a small, rounded object that you swallow and that contains medicine
stomach – n. the organ in your body where food goes and begins to break down after you swallow it
synthetic – adj. made by combining different substances; man-made, not natural
digestive tract – n. a series of organs in the body, including the stomach and the intestines
detector – n. a device for identifying or measuring the presence of something
challenge – n. a problem; an invitation to compete
transmitter – n. a device that sends out signals
