水是一切有机体的主要组成部分,全球动植物和40亿人体内含有约11200亿吨水。人类社会依赖水而生存发展。古代,人类对水取利避害,适应水而生存;近代,人类对水兴利除害,兴建工程,开发水利,控制水害;现代,随着社会和生产的发展,地球上可资利用的水日趋短缺,水体受到污染,严重影响人类生存的环境,人类逐渐认识到水是一种重要资源和环境因素,从而在更高的水平上开始对水开展了新的兴利避害活动。
世界气象组织1996年初指出:缺水是全世界城市面临的首要问题,估计到2050年,世界2/3以上的人口将生活在城市,而全球有46%的城市人口缺水,必须平衡社会经济发展和城市淡水供应管理二者之间的关系,进行水资源的储存、输送和管理的大规模工程建设。
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A、1km=()m1m=()dm1dm=()cm1cm=()mm
B、1m=()cm1m=()mm1dm=()mm
A、1m2=()dm21dm2=()cm21cm2=()mm2
B、1m2=()cm21m2=()mm21dm2=()mm2
A、1t=()kg1kg=()g1元=()角1角=()分
B、1t=()g1元=()分
②知道147cm、1m47cm、1。47m,它们之间的联系和区别。
这三个数量表示的多少都是一样的。
只不过单位不一样。147厘米和1。47米只有一个单位。像这样只有一个单位的`名数叫做()。
1米47厘米有两个单位。像这样有两个获两个以上单位的名数叫()。在这个复名数中,米是()。厘米是()。
③复名数转化成单名数。
(在复名数中,高级单位前面的数不动,只需要把低级单位前面的数除以进率,最后将结果与高级单位数合并。也可以把低级单位的数不动,用高级单位数乘进率,再把结果与低级单位数合并。)
④小数转化成复名数:小数点前是高级数
÷进率
5角=()元。想:把“角”改成“元”,要()进率(),只要把5的小数点向左移动()位。
0。5元=()角。想:把“元”改成“角”,要()进率(),只要把5的小数点向右移动()位。
Is it good for students to do some housework
Secondly, to do some housework can keep you healthy and strong ,some hard housework can be regarded as a kind of physical exercise。
Finally, to do some housework can share your parents’ work 。They must be happy if you say” Have a rest ,and I will do the housework”
So I think it is good for students to do some housework。
这是好学生做一些家务其次,做一些家务能够让你保持健康和强壮,一些硬家务可以看作是一种体育锻炼。
最后,做一些家务可以分享您的父母的工作。他们必须高兴,如果你说“休息一下,我会做家务”因此,我认为这是为学生好做一些家务。
as we know , water is very important to man, we can’t live without water. the amount of water which is suitable to drink is less and less. but some people don’t care about it .they waste a lot of water in their daily life. even worse, they pour dirty water in to rivers. they throw rubbish into rivers , too. many rivers and lakes are seriously polluted.something must be done to stop the pollution. only in this way can we live happily. if we don’t save water, the last drop of water will be a tear-drop of us.
we know that despite the fact that seventy percent of the earth's surface is covered with water, only a little part of it is fresh water. yet the demand for fresh water in our daily life and in industry seems great. moreover, with the expansion of the population and development of industry, the amount of the fresh water needed will increase even rapidly. it is estimated that if such a trend continues, the fresh water on earth will be exhausted very soon. what is worse, more and more water resources are being polluted, making the water unfit to use.
in addition,we must warn the people of the importance of water and the danger we are facing.for example, in most asian societies where rice is the staple food, the water used after cleaning rice contains various nutrients for plant growth and is an excellent detergent to flush the toilet. furthermore, the intriguing idea of converting the inexhaustible sea water to fresh water supplies will be the ultimate solution.
the importance of water(一
水的重要性(一)
the importance of water(一)
it is well-known that water is indispensable in existing, in producing and in living. and we should
not waste of a drop of water.
众所周知,在生产和生活中水是必不可少的。我们不应该浪费一滴水。
first, water is definitely important for life. as is known to us all, water is necessary to sup
port life. without water, human beings, animals and plants cannot exist at all.
首先,水对生命是非常重要的。众所周知,水是维持生命所必需的。没有水,人类,动物和植物都不复存在。 second, water is also significant for producing. for one thing, industrial production needs a lot of water, such as using water to generate electricity. for another, agricultural production is also in need of water, especially in irrigation.
《纲要》指出:教育活动内容的组织应充分考虑幼儿学习的特点和认识规律,注重趣味性、活动性,寓教育于生活、游戏之中。”活动中,我根据幼儿具体形象思维的特点,采用了幼儿喜爱的.情境表演,运用了形象生动的指偶。活动一开始,出示乌龟指偶,激发了幼儿的兴趣。让幼儿与乌龟打打招呼、说说话,在与乌龟的交流中发现乌龟不爱说话的怪脾气。接着,又让幼儿猜测“乌龟的怪脾气会给自己带来什么麻烦”,这样既给了幼儿想象的空间,又激起了幼儿学习诗歌的***。活动第二环节通过图片让幼儿欣赏、理解诗歌后,便进入了第三环节,让幼儿用指偶表演。这个环节出现了一些问题:一进入这个环节,马上就让幼儿戴上乌龟、蜗牛、青蛙三个指偶进行诗歌表演,这对于幼儿来说有点难。一些幼儿还沉浸在指偶的好玩中,没有专心地念诗歌;一些幼儿即使跟着老师边操作指偶边念诗歌,但是也没有达到指偶表演的要求。本次活动一个重点是在操作指偶的过程中学习诗歌,所以在幼儿欣赏理解诗歌的时候,教师不需要采用图片,直接可以操作指偶,让幼儿边欣赏诗歌边学习如何操作指偶。幼儿看了老师的操作后,再自己进行尝试。幼儿操作指偶时,可以先让他们操作一个指偶,如老师扮演乌龟,男孩扮演蜗牛,女孩扮演青蛙。在熟悉了指偶操作后,再让每个幼儿戴上三个指偶进行诗歌表演。最后,请幼儿三人一组,自由结伴,合作表演。这样,整个指偶表演就循序渐进,从一个人戴一个指偶表演到一个人戴三个指偶表演再到三人自选角色表演,既让幼儿学得快乐、学得容易,又能突出活动的重点,突破难点。
因此,在一个活动中,我们既要合理地运用教具,又要充分地发挥教具的价值,让教具更好地为目标服务,使活动更有成效。
1.(1四千三百七十五万4375万8000000008亿
(2十万一千万90000000九千万9000万
2.810788834558586074001
3.2.8794亿1.496亿
4.36636636
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