七年級下冊英語作文：城市綠化
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.
綠化好處多，實在是多，這是婦孺皆知的事情，可它究竟多在哪呢?又有什么好處呢?
在地球上，無論人或動物，無論你多厲害你要想生存下去就必須吸收大量的氧氣，同時放出大量的二氧化碳。可地球是原本儲存的氧氣是有限的，而且并不多，這樣氧氣早該在N年前就用光了，現(xiàn)在的氧氣又從哪里來呢?那就要靠綠色植物了。
綠色植物可以在陽光下進行光合作用，吸收二氧化碳，產(chǎn)生氧氣。研究表明：植物每生長一噸，可產(chǎn)生五噸氧。每公頃林地每天的吸收一噸二氧化碳，產(chǎn)生0.735噸氧氣;每公頃草地每天可吸收0.9噸二氧化碳，產(chǎn)生0.6噸氧氣。這樣一來地球上不就有氧氣了，城市中只要有綠化帶也可以有清新的空氣了。