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TPO閲讀解析——DESERT FORMATION

DESERT FORMATION

      The deserts, which already occupy approximately a fourth of the Earth’s land surface, have in recent decades been increasing at an alarming pace. The expansion of desert—like conditions into areas where they did not previously exist is called desertification. It has been estimated that an additional one-fourth of the Earth’s land surface is threatened by this process.

 

  1. The word threatened in the passage is closest in meaning to
  1. restricted
  2. endangered
  3. prevented
  4. rejected

Correct Answer is B.

解析:記住詞義。

 

 

Even in the areas that retain a soil cover, the reduction of vegetation typically results in the loss of the soil’s ability to absorb substantial quantities of water. The impact of raindrops on the loose soil tends to transfer fine clay particles into the tiniest soil spaces, sealing them and producing a surface that allows very little water penetration. Water absorption is greatly reduced; consequently runoff is increased, resulting in accelerated erosion rates. The gradual drying of the soil caused by its diminished ability to absorb water results in the further loss of vegetation, so that a cycle of progressive surface deterioration is established.

 

  1. According to paragraph 3, the loss of natural vegetation has which of the following consequences for soil?
  1. Increased stony content
  2. Reduced water absorption
  3. Increased numbers of spaces in the soil
  4. Reduced water runoff

Correct Answer is B.

解析:根據“Water absorption is greatly reduced”直接確定B是正確的。

 

 

There is little doubt, however, that desertification in most areas results primarily from human activities rather than natural processes. The semiarid lands bordering the deserts exist in a delicate ecological balance and are limited in their potential to adjust to increased environmental pressures. Expanding populations are subjecting the land to increasing pressures to provide them with food and fuel. In wet periods, the land may be able to respond to these stresses. During the dry periods that are common phenomena along the desert margins, though, the pressure on the land is often far in excess of its diminished capacity, and desertification results.

 

  1. The word delicate in the passage is closest in meaning to
  1. fragile
  2. predictable
  3. complex
  4. valuable

Correct Answer is A.

解析:記住詞義。

 

  1. According to paragraph 5, in dry periods, border areas have difficulty
  1. adjusting to stresses created by settlement
  2. retaining their fertility after desertification
  3. providing water for irrigation crops
  4. attracting populations in search of food and fuel

Correct Answer is A.

解析:細讀原文可知,造成沙漠化加速的原因是來自於超過自身承載力的移居行爲,因爲他們需要大量的foodfuel,土地無法適應這樣的變化,它不像自然現象能進行生態循環,所以直接就導致了沙漠化。

 

 

Four specific activities have been identified as major contributors to the desertification processes: overcultivation, overgrazing, firewood gathering, and overirrigation. The cultivation of crops has expanded into progressively drier regions as population densities have grown. These regions are especially likely to have periods of severe dryness, so that crop failures are common. Since the raising of most crops necessitates the prior removal of the natural vegetation, crop failures leave extensive tracts of land devoid of a plant cover and susceptible to wind and water erosion.

 

  1. The word progressively in the passage is closest in meaning to
  1. openly
  2. impressively
  3. objectively
  4. increasingly

Correct Answer is D.

解析:記住詞義。

 

  1. According to paragraph 6, which of the following is often associated with raising crops?
  1. Lack of proper irrigation techniques
  2. Failure to plant crops suited to the particular area
  3. Removal of the original vegetation
  4. Excessive use of dried animal waste

Correct Answer is C.

解析:問題“什么伴隨著增長的穀物?”,答案從“Since the raising of most crops necessitates the prior removal of the natural vegetation...”可以得到,因爲種田必然要開荒破壞植被,選C。這題可以用常識來做,不容易選錯,但是還是不建議用常識,因爲TOEFL考試必然是想讓你在閲讀之後理解而并非在閲讀之前理解。

 

 

  1. The phrase devoid of in the passage is closest in meaning to
  1. consist of
  2. hidden by
  3. except for
  4. lacking in

Correct Answer is D.

解析:記住詞義。

 

 

The final major human cause of desertification is soil salinization resulting from overirrigation. Excess water from irrigation sinks down into the water table. If no drainage system exists, the water table rises, bringing dissolved salts to the surface. The water evaporates and the salts are left behind, creating a white crustal layer that prevents air and water from reaching the underlying soil.

 

  1. According to paragraph 9, the ground's absorption of excess water is a factor in desertification because it can
  1. interfere with the irrigation of land
  2. limit the evaporation of water
  3. require more absorption of air by the soil
  4. bring salts to the surface

Correct Answer is D.

解析:第九段列舉了最後一個人類因素帶來的沙漠化主要原因——過度灌溉。過度灌溉帶來的土地鹽堿化。如果沒有適當的排水系統,這些過量的水會使得地下水位上升,使得一些可溶性鹽被帶到表面,而可溶性鹽析出表面之後形成的layer會阻斷空氣與水接觸layer下面的土。這一題選D

 

  1. All of the following are mentioned in the passage as contributing to desertification EXCEPT
  1. soil erosion
  2. global warming
  3. insufficient irrigation
  4. the raising of livestock

Correct Answer is C.

解析:這一題需要在全文範圍内搜素信息,主要是B選項不在剛才做題的範圍,它在第四段;另外,正確選項C容易被忽略,insufficient是不充足的灌溉,一眼望去ACD好像都見過,就B沒見過,很容易誤選B

 

 

The extreme seriousness of desertification results from the vast areas of land and the tremendous numbers of people affected, as well as from the great difficulty of reversing or even slowing the process. Once the soil has been removed by erosion, only the passage of centuries or millennia will enable new soil to form. In areas where considerable soil still remains, though, a rigorously enforced program of land protection and cover-crop planting may make it possible to reverse the present deterioration of the surface.

 

  1. 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.
  1. Desertification is a significant problem because it is so hard to reverse and affects large areas of land and great numbers of people.
  2. Slowing down the process of desertification is difficult because of population growth that has spread over large areas of land.
  3. The spread of deserts is considered a very serious problem that can be solved only if large numbers of people in various countries are involved in the effort.
  4. Desertification is extremely hard to reverse unless the population is reduced in the vast areas affected.

Correct Answer is A.

解析:句子改寫題。句子并不複雜,沒有套用從句,A選項能立即選出來。

 

  1. It can be inferred from the passage that the author most likely believes which of the following about the future of desertification?
  1. Governments will act quickly to control further desertification.
  2. The factors influencing desertification occur in cycles and will change in the future.
  3. Desertification will continue to increase.
  4. Desertification will soon occur in all areas of the world.

Correct Answer is C.

解析:全文主旨題,選C,一般來講這個題目會在最後一段找到答案,事實上也確實是。最後一段第一句提到了,別説重新綠化就連減緩沙漠化的速度都面臨著巨大的挑戰,一旦被侵蝕則可能需要幾個世紀甚至上千年才能產生新的土壤,由此可見,如果沒有强有力的措施的話,沙漠化不可避免,因此沙漠化會持續下去。當然不會像D那樣特別誇張,all areas of the world這個根本就沒提到,AB也是無中生有。

 

 

The raising of livestock is a major economic activity in semiarid lands, where grasses are generally the dominant type of natural vegetation. The consequences of an excessive number of livestock grazing in an area are the reduction of the vegetation cover and the trampling and pulverization of the soil. This is usually followed by the drying of the soil and accelerated erosion.

 

  1. Look at the four squares [ ] that indicate where the following sentence can be added to the passage.

This economic reliance on livestock in certain regions make large tracts of land susceptible to overgrazing.

Where would the sentence best fit?

Click on a square [ ] to insert the sentence in the passage.

Correct Answer is B.

解析:指示代詞this代指的livestock reliable,也就是說前面已經説過一次畜牧業依賴,這麽一來符合只有B。而B之後的是指畜牧依賴所造成的結果,這個句子放在B有承上啓下的作用。

 

  1. Direction: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Many factors have contributed to the great increase in desertification in recent decades.

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Answer Choices

  1. Growing human populations and the agricultural demands that come with such growth have upset the ecological balance in some areas and led to the spread of deserts.
  2. As periods of severe dryness have become more common, failures of a number of different crops have increased.
  3. Excessive numbers of cattle and need for firewood for fuel have reduced grasses and trees leaving the land unprotected and vulnerable.
  4. Extensive irrigation with poor drainage brings salt to the surface of the soil, a process that reduces water and air absorption.
  5. Animal dung enriches the soil by providing nutrients for plant growth.
  6. Grasses are generally the dominant type of natural vegetation in semiarid lands.

Correct Answer is ACD.

解析:EF是無關緊要是細節,不管敘述正確與否,直接忽視;B選項,隨著嚴重的乾旱期變得普遍,很多不同農作物的失敗開始增加,雖然我不記得讀到過這一句,但是這是個細節,和main factors無關。ACD分別從人口遷移、過度放牧和過度灌溉3個方面闡述促成沙漠化的因素。

 

*綠色字體表示生詞

*藍色字體表示TPO題選取的單詞

*紅色表示正確答案+多次重复的单词

 

主目錄:https://www.v2know.com/MainPage/Category/TOEFL

This article was last edited at 2021-05-20 16:32:38

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