文勇的新托福黄金&ccedil

expansionofirrigationagricultureespeciallyfromthe1950

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Unformatted text preview: build big bodies, they cannot compete with other plants for space, water, or sunlight. These plants are termed opportunists because they rely on their seeds’ falling into settings where competing plants have 134 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 been removed by natural processes, such as along an eroding riverbank, on landslips, or where a tree falls and creates a gap in the forest canopy. 5. The word dispersal in the passage is closest in meaning to ○Development ○ Growth ○ Distribution ○ Protection 6. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. ○Because their seeds grow in places where competing plants are no longer present, dandelions are classified as opportunists. ○Dandelions are called opportunists because they contribute to the natural processes of erosion and the creation of gaps in the forest canopy. ○The term opportunists apply to plants whose seeds fall in places where they can compete with the seeds of other plants. ○The term opportunists apply to plants whose falling seeds are removed by natural processes. Paragraph 7 在 The opposite of an opportunist is a competitor. These organisms tend to have big bodies, are long­ lived, and spend relatively little effort each year on reproduction. An oak tree is a good example of a competitor. A massive oak claims its ground for 200 years or more, outcompeting all other would­be canopy trees by casting a dense shade and drawing up any free water in the soil. The leaves of an oak tree taste foul because they are rich in tannins, a chemical that renders them distasteful or indigestible to many organisms. The tannins are part of the defense mechanism that is essential to longevity. Although oaks produce thousands of acorns, the investment in a crop of acorns is small compared with the energy spent on building leaves, trunk, and roots. Once an oak tree becomes established, it is likely to survive minor cycles of drought and even fire. A population of oaks is likely to be relatively stable through time, and its survival is likely to depend more on its ability to withstand the pressures of competition or predation than on its ability to take advantage of chance events. It should be noted, however, that the pure opportunist or pure competitor is rare in nature, as most species fall between the extremes of a continuum, exhibiting a blend of some opportunistic and some competitive characteristics. 7. The word massive in the passage is closest in meaning to ○ Huge ○ Ancient ○ Common ○ Successful 8. All of the following are mentioned in paragraph 7 as contributing to the longevity of an oak tree EXCEPT ○ The capacity to create shade ○ Leaves containing tannin ○ The ability to withstand mild droughts and fire ○ The large...
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.

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