电脑的好处太多了.可以用来用多媒体学习,还能玩游戏,看网络电视,看世界各地的新闻,查找有用的信息资料.真是好处太多了,不过玩过头了就有坏处了,就象我现在还在这里上网不睡觉一样.
好处坏处我都说说吧:
现今的社会科技发达,电脑的使用已经非常普遍,差不多每家每户都有一台电脑.电脑的用途广泛,而且方便快捷,深受人们的欢迎,但与此同时它带来很多的坏处.电脑的好处有很多,例如可以方便我们搜集资料.当我们想做一个专题习作,但又缺乏资料,只要我们上网浏览,就可以立刻找到很多与该专题习作有关的资料,非常方便.透过电脑可以提高学生的语文水平,现在互联上设有「每日一篇」阅读计划,我们每天只需五至十分钟时间上网就可以阅读一篇优质的文章,并完成课后练习.如此下去,日积月累,我们的语文水平一定可以大大提高.如果同学在功课上遇到不懂的地方,只要一上网,就会有人为我们解决难题.
不过,电脑也为我们带来很大的坏处.电脑会影响我们的视力,如果我们长时间望?电脑的屏幕,不让眼睛作适当的休息,这样会影响我们的视力,引致近视,更严重的可能会引致「乾眼病」.它也会影响我们的学业,如果我们太过沉迷网上游戏线和「」,把学业置诸不理,学业成绩因而下降,甚至无心向学.不过,最严重的是影响了人与人之间的沟通,由於电脑实在太不方便,人们只要利用互联网便能传递彼此间的讯息,甚至连通的时间也减少了；长此下去,这个社会就会变得冷漠,人与人之间的隔膜也会越来越大.唉!电脑带来的坏处多麼可怕啊!
「水能载舟,也能覆舟」,我深信只要我们懂得克服自己,懂得分配时间,善用电脑,那麼,电脑将会是我们生活上的好帮手.
The advantage of the computer too much. Can be used with multimedia learning, can also play games, watch network TV, watching the news all over the world, to find the useful information. Is really too many benefits, but playing too much is bad, just like I'm still here to get to the Internet without sleep.
Good bad I say:
Today's society science and technology developed, the use of computers has become so common that almost every household has a computer. Computers are very versatile, and convenient and quick, is popular among people, but at the same time it brings a lot of harm. The benefits of the computer has a lot of, for example can we collect data. When we want to do a special project, but the lack of information, as long as we are surfing the Internet, you can immediately find a lot of information related to the project project, is very convenient. Through the computer can improve the students' Chinese level, now on the Internet with \"a\" daily reading plans, we just five to ten minutes a day surfing the Internet can read a good article, and complete the practise after class. So, accumulate over a long period, our level of Chinese language will be greatly improved. If students in classes meet don't understand the place, as long as the one on the Internet, someone will solve the problem for us.
However, the disadvantages of computer also bring us a lot. The computer will affect our vision, if we looked at for a long time? The computer screen, don't let an eye to make proper rest, this will affect our vision, cause myopia, more serious may cause \"dry eye\". It will also affect our studies, if we are too addicted online game thread and \"\", the school all ignore, academic performance has fallen, even inadvertently for school. However, the most seriously affected the communication between people, is because the computer is too inconvenient, as long as people use the Internet can transfer information between each other, even connected phone time is also reduced; Long the bottom go to, the society will become indifferent, the diaphragm between people also will be more and more big. Alas! How terrible the disadvantage brought by computer!
\"The water boat, also can sink it\", I am convinced that as long as we know how to overcome yourself, know the distribution of time, make use of the computer, so, the computer will we live on is a good helper.
二氧化碳的“功”与“过”
随着现代工业的发展,从工厂和汽车等排放出来的二氧化碳日益增多.这是目前地球上出现温室效应的最主要原因.因此,二氧化碳常被人看作是“废物”,甚至当作危险的“敌人”.其实二氧化碳对人类和其它生物作出了重大贡献.
二氧化碳是绿色植物光合作用、生长必须的营养物质.叶子中的叶绿素在日光照射下都能完成一个很奇妙的变化,把叶子吸收的二氧化和根部输送来的水分转变为糖、淀粉以及氧气（光合作用）,6CO2＋6H2O → C6H12O6＋6O2.实验证明,空气中二氧化碳浓度增大可以使农作物增产,因此二氧化碳有“气肥”之称.
二氧化碳可以贮藏粮食、水果、蔬菜.用二氧化碳贮藏的食品由于缺氧和二氧化碳本身的抑制作用,可有效地防止食品中细菌、霉菌、虫子生长,避免变质和有害健康的过氧化物产生,并能保鲜和维持食品原有的风味和营养成分.二氧化碳不会造成谷物中药物残留和大气污染.
固态二氧化碳俗称干冰.它除了常被用于肉类等食物的冷冻保鲜还用于人工降雨.当空气中含有大量水蒸气,却因缺少凝结核心而未能凝成雨滴时,用飞机将干冰撒向空中,由于干冰迅速气化吸热,四周气温骤降结出许多小冰晶,水蒸气就能凝成水滴而下雨.
二氧化碳密度比空气大,不能燃烧也不能支持燃烧,可用于灭火.但有些活动性强的金属,例如镁条,点燃后放入二氧化碳里能够继续燃烧：2Mg＋CO2→2MgO＋C 因此,我们通常所说的二氧化碳不能支持燃烧是有条件的.
无色、无臭的气体二氧化碳有个怪脾气,如果它在空气中的浓度超过5%,就会刺激人的呼吸中枢神经,使呼吸量增加两倍,并且有不舒服的感觉.一旦吸入高浓度 CO2,部分人可先感头昏、心悸、迅速出现语妄、掠厥、昏迷,若不及时脱离现场抢救,可发生脑水肿、肺水肿,并因呼吸循环衰竭而死亡.在岩洞、枯井、地窖中可能聚集着二氧化碳,人若误入其中则窒息死亡.为此,人们下到深井之前要进行明火试验,因二氧化碳不支持燃烧,明火若熄灭就表明可能有二氧化碳气体.
近几十年来,由于人类消耗的能源急剧增加,森林遭到破坏,大气中CO2的含量不断上升.CO2就像温室的玻璃一样,并不影响太阳对地球表面的辐射,但却能阻碍由地面反射回高空的红外辐射,这就像给地球罩上了一层保温膜,使地球表面气温增高,产生“温室效应”.能产生“温室效应”的气体除CO2外,还有臭氧(O3)、CH4、氟氯代烷(该类化合物包括20多种,其中主要有CCl3F、CCl2F2)等.全球变暖会对人类生活带来很大影响.地球温度上升,将导致寒带和两极的冰川大量融化,海平面因而会上升,从而淹没地势较低的沿海城市及河流三角洲；气温上升会使干旱的热带地区更加干旱,并使土地沙漠化的进程加快,自然灾害的进程加快,自然灾害也越来越频繁,甚至会导致许多物种的加速灭绝.
为了保护人类赖以生存的地球,人类应共同防止温室效应进一步增强.我们可以采取以下措施：节约能源、减少使用煤、石油、天然气等化石燃料；更多地利用太阳能、风能、地热等；限制并逐步停止氟氯代烷的生产和使用；大力植树造林,严禁乱砍滥伐森林等.
朋友家有一只猫咪,金黄的皮毛,见了人总是怯怯的,一双大眼睛闪烁着拘谨与不安.朋友把它从地上抱起,向我讲起了它离奇的身世.
小区附近有一只野猫,朋友曾好几次见到它在阴暗的角落里出没.野猫也有爱情,爱情的结晶是七只猫仔.野猫妈妈无力抚养这么多后代,它自己过的也是饥一顿饱一顿 的生活.小猫断奶之后,它把小猫衔起来,放到小区住户的门口,然后在暗处躲起来等待,一直等到这户人家发现了小猫.
即使小猫被高高兴兴地抱进家里,野猫妈妈也并不立即离去,它要在外面多耽一会儿,直到确认小猫已被这个家庭收纳,才回窝里去衔下一只.听说有几户抱回小猫的是小孩子,不到五分钟后小猫就被家里的大人扔了出来,这时野猫妈妈会衔起它到另外一家去碰运气.
最后有只小黑猫始终无人接纳,也许它颜色不够吉祥,也许是小区的宠物已趋饱和,总之是野猫妈妈自己抚养了它.
朋友点点怀里猫咪的鼻子说：“还记得你妈妈吗?你妈妈不要你了.你想妈妈不?”猫咪“喵呜”地叫了一声作为回答.
朋友讲完了小猫的故事,我陷入良久的沉思.
野猫从来都为人所憎恶,它们在夜色中出没,身上沾满污秽,犹如撒旦的使徒.我曾耳闻目睹许多人类迫害野猫的事件,其中不乏令人发指的残忍.反过来,在野猫眼中,人类也当是它们的头号天敌,你很难接近一只野猫五米之内,它们闻到人声会立即远遁.
那为什么野猫妈妈甘冒大险,将自己的亲生骨肉交到人类手里呢?
我想,这只野猫妈妈一定是家猫出身,它也曾享受过家庭的温暖,主人的爱怜,它了解人类,深知幼小的猫咪对大多数人都有一种强烈的诱惑.
The Chinese New Year The Chinese New Year is a festival whose Chinese are most important.The history of the Chinese New Year is very long.Stanza front stick in an on the face the New Year's Day of the...
The Spring Festival
Far and away the most important holiday in China is Spring Festival, also known as the Chinese New Year. To the Chinese people it is as important as Christmas to people in the West. The dates for this annual celebration are determined by the lunar calendar rather than the Gregorian calendar, so the timing of the holiday varies from late January to early February.
To the ordinary Chinese, the festival actually begins on the eve of the lunar New Year's Day and ends on the fifth day of the first month of the lunar calendar. But the 15th of the first month, which normally is called the Lantern Festival, means the official end of the Spring Festival in many parts of the country.
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