英语作文大全

　　Most people believe that regular hand-washing is the best way to prevent infections. And they’re right: hand-washing does prevent certain infections, but too much washing can actually help some infections along.What’s going on?

　　Right now, there are millions of bacteria from hundreds of different species happily residing on your hands, not to mention your teeth, gums, eyes and ears. These bacteria are either transients or residents. Washing your hands helps remove transientbacteria that are just visiting from foreign places like the sink, doorknob and even other people’s hands. Washing shouldn’t remove your hands’ own resident bacteria,though.

　　While it’s hard to imagine your hands as a bacterial homeland, these residents are perfectly normal and are important in maintaining your health. They help prevent transientbacteria from settling in, and each resident keeps other residents from overpopulating.

　　If you scrub your skin too frequently, especially with anti-bacterial soap, you could upset resident bacteria, leading to the overpopulation of certain species and local skin infections. Scrubbing away residents might also let transients move in and cause disease. Finally, over washing could break down the skin itself. This allows harmless skin residents to go beneath the skin, where they can become dangerous transients.

　　So, while a good wash with soap and water is still a great idea, overwashing might lead to some unpleasant symptoms, not to mention inflamed and unsightly hands.

标签：有趣一节课

热门成语

• 风不鸣条  和风轻拂，树枝不发出声响。比喻社会安定。
• 安分知足  安于本分，对自己所得到的待遇知道满足。
• 白圭之玷  白玉上的一个斑点。比喻人或物大体很好，只是有些小缺点。
• 飞沙走砾  沙：沙土；砾：小石块。沙土飞扬，小石块滚动。形容风势很猛。
• 百思不解  百般思索也无法理解。
• 诽誉在俗  诽：指诽谤；誉：赞扬；俗：风气、习惯。诽谤或赞扬在于当时的风习。后来引申指风气、习惯的作用非常大。
• 分毫不爽  比喻没有丝毫差错。
• 挨肩擦背  形容人多拥挤。
• 飞黄腾达  飞黄：传说中神马名；腾达：上升，引伸为发迹，宦途得意。形容骏马奔腾飞驰。比喻骤然得志，官职升得很快。
• 博闻辩言  博：多。闻：传闻。辩言：巧言。形容道听途说，似是而非的言论。
• 不齿于人  指被人看不起。
• 不打不成相识  指经过交手，彼此了解，结交起来就更投合。
• 不恶而严  并不恶声恶气，但很威严，使人知敬畏。
• 飞蛾投火  象蛾子扑火一样。比喻自找死路、自取灭亡。
• 飞云掣电  掣：闪过。像流云飞和闪电一样。形容非常迅速。