资料题：According to the article, the main purpose of a label is to（　）。

Every word on a label describing a food, a drug, a cosmetic, or a medical device is important in protecting you and your family from buying an inferior product, from misusing a good one,from being tricked by dangerous quackery (欺骟行为), or from unknowingly possessing an item harmful to health.First of all, the label on a can or package of food must be completely truthful.If a loaf of bread is made with soy flour, the loaf cannot be labeled as white bread.A label must not be misleading.This restriction is somewhat vague and therefore cannot prevent all violations.Although the government tries to eliminate all misleading labels, the consumer must nevertheless be always on guard.Just because a can of sardines has a fancy-sounding foreign name, don't take for granted that the fish were imported.It is the law too that manufacturers must list their names and places of business on their labels.Manufacturers must use common names in identifying their products so that anyone can readily understand what he is buying.Synthetic foods must be prominently labeled as artificial.Foods composed of two or more ingredients must bear labels listing all ingredients in the order of predominance.