【正文】 ot 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 cohesiontension 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 cohesion (the attraction between water molecules) are so great that the strength of a column of water pares 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) Four2. 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 weak3. The word demonstrated in line5 is closest in meaning to(A) ignored (B) showed (C) disguised(D) distinguished4. What do the experiments mentioned in lines 46 prove? (A) Plant stems die when deprived of water(B) Cells in plant stems do not pump water(C) Plants cannot move water to high altitudes(D) Plant cells regulate pressure within stems5. How do botanists know that root pressure is not the only force that moves w ater 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 plant39。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 11 refers to(A) top (B) tree (C) water(D) cohesiontension theory.8. The word there in line 10 refers to(A) treetops(B) roots(C) water columns(D) tubes9. What causes the tension that draws water up a plant? (A) Humidity(B) Plant growth(C) Root pressure(D) Evaporation10. The word extend in line 13 is closest in meaning to(A) stretch (B) branch (C) increase (D) rotate11. 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 in strong.(C) The living cells of plants push the water molecules together. (D) Atmospheric pressure supports the columns.12. Why does the author mention‖ steel wire‖ in line 17? (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 water(D) To emphasize the strength of cohesive forces in water13. Where in the passage does the author give an example of a plant with low root pressure? (A) Lines 23(B) Lines 35 (C) Lines 67 (D)Lines8Question 1422Mass transportation revised the social and economic fabric of the American city in three fundamental ways. It catalyzed physical expansion, it sorted out people and land uses, and it accelerated the inherent instability of urban life. By opening vast areas of unoccupied land for residential expansion, the omnibuses, horse railways, muter 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。 there was always a huge surplus of subdivided, but vacant, land around Chicago and other cities. These excesses underscore a feature of residential expansion re lated 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 land near or outside city borders where transit lines and middleclass 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 transportation 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 mercial and residential districts.(C) Changes in life in the inner city. (D) Increasing standards of living.16. The word vast in line 3 is closest in meaning to(A) large (B) basic (C) new (D) urban17. The word sparked in line 8 is closest in meaning to(A) brought about(B) surrounded(C) sent out(D) followed18. 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