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　　[TOEFL全真试题（2-2）]

　　VOCABULARY AND READING COMPREHENSION

　　Questions 1-13

　　Atmospheric pressure can support a column of water up to 10 meters high. But

　　plants can move water much higher, the sequoia tree can pump water to its very top,

　　more than 100 meters above the ground. Until the end of the nineteenth century , the

　　movement of water s in trees and other talls plants was a mystery. Some botanists

　　hypothesized that the living cells of plants acted as pumps, but many experiments

　　demonstrated that the stems of plants in which all the cells are killed can still move

　　water to appreciable heights. Other explanations for the movement of water in plants

　　have been based on root pressure, a push on the water from the roots at the bottom of

　　the plant. But root pressure is not nearly great enough to push water to the tops of tall

　　trees, Furthermore, the conifers, which are among the tallest trees have unusually low

　　root pressures.

　　If water is not pumped to the top of a tall tree, .and if it is not pushed, to the top of a

　　tall tree, then we may ask. How does it get there? According to the currently accepted

　　cohesion-tension theory, water is pulled there. The pull on a rising column of water in a

　　plant results from the evaporation of water at the top of the plant. As water is lost from

　　the surface of the leaves,a negative pressure or tension is created. The evaporated

　　water is replaced by water moving from inside the plant in unbroken columns that

　　extend from the top of a plant to its roots. The same forces that create surface tension

　　in any sample of water .are responsible for the maintenance of these unbroken columns

　　of water. When water is confined in tubes of very small bore, the forces of cohestion

　　(the attraction between water molecules) arc so great that the strength of a column of

　　water compares with the strength of a. steel wire of the same diameter. This

　　第2篇 中考英语满分作文 A Letter to the University President

　　〖预览〗Direction： For this part， you are allowed thirty minutes to write a composition on the topic： A letter to the university president about the canteen service on campus， you should write at least 100 words， and base your composition on the outline given in Chinese below：　　　　假设你是李伟，请你就本校食堂的状况给校长写了一封信，内容涉及食堂的饭菜质量、价格、环境、服……【全文阅读：中考英语满分作文 A Letter to the University President】

　　第3篇 初中英语范文　Adjust Our Eyesight-调整我们的视力

　　〖预览〗我和爸爸都有很好的视力，可是妈妈正相反。我们俩想帮助妈妈调整好视力，这样她不带眼镜也能看清东西了。可是有趣的是，我和爸爸也有一些东西是视而不见的，比如零乱的房间，蒙尘的家具和肮脏的地板。但妈妈就能清楚地发现并及时打扫干净。　　Father and I both have good eyesight, but mother doesnt. We want to help mother adjust her eyesight and make her see things clearly without glasses. But it is interesting enough that there are things fathe……【全文阅读：初中英语范文　Adjust Our Eyesight-调整我们的视力】

　　第4篇 奥运英语作文：中国跳水队(Diving into Gold: Chinas Dream Team)

　　〖预览〗奥运英语作文：中国跳水队(Diving into Gold: Chinas Dream Team)　　For Chinas diving team, nothing speaks louder of their "dream team”. China has unquestioned domination in diving. The Chinese diving team claimed five golds at 2000 Sydney Olympics and further took a record six at 2004 Athens Olympics, contributing more Olympic ……【全文阅读：奥运英语作文：中国跳水队(Diving into Gold: Chinas Dream Team)】

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　　〔TOEFL全真试题（2-2）〕

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