TOEFL全真试题阅读部分

TOEFL全真试题阅读部分

　　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 , themovement 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 cohesive strength permits columns of water to be pulled to great heights without being broken.

　　1. How many theories does the author mention?

　　(A) One

　　(B) Two

　　(C) Three

　　(D) Four

　　2. The passage answers which of the following questions ?

　　(A) What is the effect of atmospheric pressure on foliage?

　　(B) When do dead cells harm plant growth?

　　(C) How does water get to the tops of trees?

　　(D) Why is root pressure weak?

　　3. The word "demonstrated" in line 6 is closest in meaning to

　　(A)ignored

　　(B) showed

　　(C) disguised

　　(D) distinguished

　　4. What do the experiments mentioned in lines 6-8 prove?

　　(A) Plant stems die when deprived of water.

　　(B) Cells in plant sterns do not pump water.

　　(C) Plants cannot move water to high altitudes.

　　(D) Plant cells regulate pressure within stems.

　　5. How do botanists know that root pressure is not the only force that moves water in plants?

　　(A) Some very tall trees have weak root pressure.

　　(B) Root pressures decrease in winter.

　　(C) Plants can live after their roots die.

　　(D) Water in a plant s roots is not connected to water in its stem.

　　6. Which of the following statements does the passage support?

　　(A) Water is pushed to the tops of trees.

　　(B) Botanists have proven that living cells act as pumps.

　　(C) Atmospheric pressure draws water to the tops of tall trees.

　　(D) Botanists have changed their theories of how water moves in plants.

　　7. The word "it" in line 13 refers to

　　(A) top

　　(B) tree

　　(C) water

　　(D) cohesion-tension theory

　　8. The word "there" in line 15 refers to

　　(A)treetops

　　(B) roots

　　(C) water columns

　　(D) tubes

　　9. What causes the tension that draws water up a plant?

　　(A) Humidity

　　(B) Plant growth

　　(C) Root pressure

　　(D) Evaporation

　　10. The word "extend" in line 19 is closest in meaning to

　　(A) stretch

　　(B) branch

　　(C) increase

　　(D) rotate

　　11. According to the passage, why does water travel through plants in unbroken columns?

　　(A) Root pressure moves the water very rapidly.

　　(B) The attraction between water molecules is strong.

　　(C) The living cell of plants push the water molecules together.

　　(D) Atmospheric pressure supports the columns.

　　12. Why does the author mention steel wire in line 24?

　　(A) To illustrate another means of pulling water

　　(B) To demonstrate why wood is a good building material

　　(C) To indicate the size of a column of winter

　　(D) To emphasize the strength of cohesive forces in water

　　13. Where in the passage does the author give an example of a plant with low root pressure?

　　(A.) Lines 3-5

　　(B) Lines 6-8

　　(C) Lines 11-12

　　(D) Lines 13-14

Questions 14-22

　　Mass transportation revised the social and economic fabric of the American city in three fundamental ways. It catalyzed physical expansion, it sorted outpeople and land uses, and it accelerated the inherent instability of urbon life. By opening vast areas of unoccupied land for residential expansion, the omnibuses, horse railways, commuter trains, and electric trolleys pulled settled regions outward two to four times more distant from city centers than they were in the premodern era. In 1850, for example, the borders of Boston lay scarcely two miles from the old business district by the turn of the century the radius extended ten miles. Now those who could afford it could live far removed from the old city center and still commute there for work, shopping, and entertainment. The new accessibility of land around the periphery of almost every major city sparked an explosion of real estate development and fulled what we now know as urban sprawl.Between 1890 and 1920, for example, some 250,000 new residential lots were recorded within the borders of Chicago, most of them. located in outlying areas. Over the same period, another 550,000 were plotted outside the city limits but within the metropolitan area. Anxious to take advantage of the possibilities of commuting, real estate developers added 800,000 potential building sites to the Chicago region in just thirty years-lots that could have housed five to six millionpeople.

      Of course, many were never occupied; there was always a huge surplus of subdivided, but vacant, land around Chicago and other cities. There excesses underscore a feature of residential expansion related to the growth of mass transportation urban sprawl was essentially unplanned. It was carried out by thousands of small investors who paid little heed to coordinated land use or to future land users. Those who purchased and prepared land for residential purposes, particularly and near or outside city borders where transit lines and middle-class inhabitants were anticipated, did so to create demand as much as to respond to it.

      Chicago is a prime example of this process. Real estate subdivision there proceeded

much faster than population growth.

　　14. With which of the following subjects is the passage mainly concerned?

　　(A) Types of mass transportation

　　(B) Instability of urban life

　　(C) How supply and demand determine land use

　　(D) The effects of mass trans- city portation on urban expansion

　　15. The author mentions all of the following as effects of mass transportation on cities EXCEPT

　　(A) growth in city area

　　(B) separation of commercial and residential districts

　　(C) changes in life in the inner city

　　(D) increasing standards of living.

　　16. The word "vast" in line 4 is closest in meaning to

　　(A) large

　　(B) basic

　　(C) new

　　(D) urban

　　17. The word "sparked" in line 12 is closest in meaning to

　　(A) brought about

　　(B) surrounded

　　(C) sent out

　　(D) followed

　　18. Why does the author mention both Boston and Chicago?

　　(A)To demonstrate positive and negative effects of growth

　　(B) To show that mass transit changed many cities

　　(C) To exemplify cities with and without mass transportation

　　(D) To contrast their rates of growth

　　19. The word "potential" in line 18 is closest in meaning to

　　(A) certain

　　(B) popular

　　(C) improved

　　(D) possible

　　20.The word "many" in line 21 refers to

　　(A) people

　　(B) lots-

　　(C) years

　　(D) developers

　　21.According to the passage, what was one disadvantage of residential expansion?

　　(A) It was expensive.

　　(B) It happened too slowly.

　　(C) It was unplanned.

　　(D) It created a demand for public transportation.

　　22.The author mentions Chicago in the second paragraph as an example of a city

　　(A) that is large

　　(B) that is used as a model for land development

　　(C) where land development exceeded population growth

　　(D) with an excellent mass transportation system