七年级下册英语作文：城市绿化

　　Green benefits more, it is much, this is the layman, but it how? What good?

　　On the earth, whether people or animals, no matter how much you if you want to survive, you must absorb a large number of oxygen, emit large amounts of carbon dioxide at the same time. But the earth is originally stored oxygen is limited, and there are not many, so oxygen should run out in N years ago, oxygen and from where to now? That is about to rely on the green plants.

　　Green plants can be in the sun for photosynthesis, absorb carbon dioxide to produce oxygen. Research shows that: each plants grow a ton, can produce five tons of oxygen. Absorb one ton of carbon dioxide per hectare of forest land every day, 0.735 tons of oxygen; Grass absorbs 0.9 tonnes of carbon dioxide per day per hectare, produce 0.6 tons of oxygen. So do not have oxygen on earth, as long as there is green in the city can also have the fresh air.

　　绿化好处多，实在是多，这是妇孺皆知的事情，可它究竟多在哪呢?又有什么好处呢?

　　在地球上，无论人或动物，无论你多厉害你要想生存下去就必须吸收大量的.氧气，同时放出大量的二氧化碳?？傻厍蚴窃敬⒋娴难跗怯邢薜?，而且并不多，这样氧气早该在N年前就用光了，现在的氧气又从哪里来呢?那就要靠绿色植物了。

　　绿色植物可以在阳光下进行光合作用，吸收二氧化碳，产生氧气。研究表明：植物每生长一吨，可产生五吨氧。每公顷林地每天的吸收一吨二氧化碳，产生0.735吨氧气;每公顷草地每天可吸收0.9吨二氧化碳，产生0.6吨氧气。这样一来地球上不就有氧气了，城市中只要有绿化带也可以有清新的空气了。