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Why do we cry? Can you imagine life without tears? Not only do tears keep your eyes lubricated, they also contain a substance that kills certain bacteria so they can't infect your eyes. Give up your tears, and you'll lose this on-the-spot defense. Nobody wants to give up the flood of extra tears you produce when you get something physical or chemical in your eyes. Tears are very good at washing this irritating stuff out. Another thing you couldn't do without your tears is cry from joy, anger or sadness. Humans are the only animals that produce tears in response to emotions, and most people say a good cry makes them feel better. Many scientists, therefore, believe that crying somehow helps us cope with emotional situations.
我们为什么会哭呢？你能想像生活没有了眼泪会是什么样么？眼泪不仅可以让眼睛保持湿润，还包含了一种可以杀死感染眼部的细菌。没有了眼泪，你就失去了现场的防护。如果你眼睛里进了什么东西或者化学品，没有人会不想制造一大堆多余眼泪出来的。眼泪很擅长把这些烦人的东西冲出来。另外一件你不能没有眼泪的事就是由快乐、生气或者悲伤而来的眼泪。人类是唯一一种可以因为感情而产生眼泪的动物，而且很多人说如果能痛哭一场会感觉好不少。因此很多科学家相信哭泣可以帮我们应对情感问题。