保护城市空气干净的英语作文【一】
A tiger is a kind of catamount animal. It looks like a cat, but much bigger than a cat. A tiger is very ferocious and it eats mainly meat. It has yellow and black streaks all over its body and it looks very beautiful. Its tail is long and strong and it can hit its quarry dying.
Tigers live in the thick forests and small animals in the forests are tigers' food.
During the past years, many forests have been cut down and the living conditions of the tigers are becoming worse and worse. There are fewer tigers left in the world now. Tigers are the animals of the world, and they should have their own living spaces. We must do our best to protect the tigers and their living environment.
保护城市空气干净的英语作文【二】
Giant Panda is our national treasure, the state can be said for the protection of giant pandas put a lot of human and material resources giant now has been the world's people the protection and care, which is a good thing, of course, the Tibetan antelope as the country's animal protection , The National People have been recognized, however, this tiger? The poor will be extinct Siberian tiger who is going to have a genuine concern and care a little bit?
According to statistics, the Siberian tiger left at present, less than 20, still such a small number of these survive, has had imagined. Two years ago, in the mountains of Huanren, Liaoning found to be a man to die under the presentation of the Siberian tiger, from this we can see that the above countries and the people of the importance we attach to it, this first Manchurian tiger is actually how the dead do not Conclusion, and the other is only from the northeast where hu came to the place where the wonder and the third is the matter did not rise to the national media in particular. This really puzzled the other person you! Is it really the other tiger who fear love is not worth it, it really fate of the Siberian tiger so?
Towering mountains should not unique to human beings, should not have dense forest unique to human beings, rivers clear this should not be unique to human beings, the Siberian tiger survival of this nature should not be unique to human beings. Siberian tiger to the left of a piece of heaven and earth to survive it, the High IQ is the human species, there are still ways to leave that piece of local survival, and the tiger have to leave that piece of the local dead; you save tigers, is the human population control, engage in Family planning, and the Siberian tiger is scarce Rending it! Now we can hear the cries of tigers in the future even the Siberian tiger can be heard the cries.
保护城市空气干净的英语作文【三】
空气很普通，可是，空气也包含着许许多多有趣的学问，你知道空气是怎样组成的吗?你知道为什么几乎所有活着的生物都离不开空气吗?你知道二氧化碳和水是怎样雕凿出天然艺术之美的吗?你知道有些有毒气体是怎样化合而成的吗?
首先.咱们给空气的成员们编一本户口簿，按三类來登记造册。笫一类是以氮气、氧气和稀有气体组成的含量几乎恒定不变的成分。以不含水蒸气的干燥空气计算，氮气占总体积的百分之七十八，氧气约占百分之二十一，而其他的氩气、氮气、氖气等许多空气成员加起来不过只占百分之零点几。这是多么大的差异啊!第二类是包括二氧化碳，水蒸汽、尘埃粒子等含量可变的成分。奇特的是，它们在大气中没有固定比例，多的时候可达大气总体积的百分之四，少的时候连百分之一都够不上。笫三类就是大气里报临时户口的成员了，它们大都是有害气体,如氨、二氧化硫、一氧化碳等等，种类竟达上千种!
在含量不变的空气成员种，人们交口称颂的当然是氧气了。这倒不是人类庇护氧气,而是氧气的确有功于一切生物。一切活着的生物进行生命活动都需要能量，那么这些能量又是从哪里来的呢?能量贮藏在生物体的有机物中，生物体吸入氧气后，氧气就与贮藏能量的有机物发生了奇妙的化学反应，把有机物转化成无机物，就释放出了能量。这就是氧气的主要特性。此外，氧气还有促成植物光合作用、帮助燃烧等等许多特性。
在祖国的西南石灰岩地区,这里奇峰异洞、怪石如林，身临其境的人无不惊叹大自然的高超技艺。那么，这是谁雕凿的呢?这就是二氧化碳和水。石灰岩的'主娈成分是一种碳酸钙的物质，当含又二氧化碳的水和石灰岩层接触时,碳酸钙就和二氧化碳、水起化学反应，把石灰岩溶解成碳酸氢钙,混合在水屮。经过年复一年的岩溶过程，岩层外表就会出现各式各样的形态。同时,溶有碳酸氢钙的水流，由于二氧化碳“逃跑”以及水分蒸发，又会形成石钟乳、石笋这样的奇丽景色。二氧化碳和水就是这样雕出天然艺术之美來的。
前而提过空气中的败类冇一个叫二氧化硫的家伙，它的“出生”倒处挺有意思的。原來在煤、石油等燃料中，含有少量的硫,一般占总体积的百分之一至百分之七。因为燃烧需要氧气,在燃烧过程屮，硫和氧化合，形成气态的二氧化硫放出來，二氧化硫有时可以转变为三氧化硫。另外，空气还可以进行各种各样的化合。例如:二氧化硫遇水汽化合成硫酸雾，一氧化氮和氣气合成二氧化氮……它们都是有毒的，是大气污染的罪魁祸首。
说了这么多，你一定对空气有了大概的了解吧?空气的学问还冇很多。它对人类有许多许多的用处，但也有不少的害处。我们只冇掌握了空气的知识，才能让它向有利的方向发展，更好地为人类服务。同学们，让我们努力探索空气的奥秘吧!
