VOA慢速英语:Scientists Create Method to Test Food and Drugs for Purity

contaminate – v. to make something dangerous, dirty or impure by adding something harmful or undesirable to it

brake – n. a device for slowing or stopping something (such as a wheel or vehicle)

talcum powder – n. a soft, white powder that is used to make your skin feel dry and smooth

iodine – n. a chemical element that is used especially in medicine and photography

cumbersome – adj. complicated and hard to do

pharmacy – n. a store or part of a store in which drugs and medicines are prepared and sold

take it for granted – expression to believe or assume that something is true or probably true without knowing that it is true; to fail to properly notice or appreciate someone or something that is helpful or important to you

extent – n. used to indicate the degree to which something exists, happens or is true

portable – adj. easy to carry or move around