眼泪的成分类似唾液,是一种弱酸性透明的无色液体,成分绝大部分是水,并含有少量无机盐、蛋白质、溶菌酶、免疫球蛋白A等其它物质。眼泪分三种。第一种是眨眼间产生的,即所谓的“基础泪”。这种眼泪主要是维护眼睛发挥正常功能。第二种是因为条件反射流出的眼泪,如切洋葱时流下的泪水,这种泪水是由保护性的反应产生的,通过这种保护,我们可以防止异物和脏东西进入眼睛里。第三种是只有人类才有的眼泪,即充满感情的泪水。当我们悲伤、惊喜时,很难 The composition of tears is similar to saliva, is a weak acid transparent colorless liquid, most of the ingredients are water, and contains a small amount of inorganic salts, proteins, lysozyme, immunoglobulin A and other substances. There are three kinds of tears. The first is generated in the blink of an eye, the so-called “basic tears.” This tear is mainly to maintain normal eyesight function. The second is tears shed from conditioned reflexes, such as tears shed when cutting onions. This tear is produced by a protective reaction that prevents foreign objects and dirt from entering our eyes. The third is the only human tears, full of emotion tears. When we are sad, surprise, it’s hard