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1995年10月托福阅读全真试题(1) |
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| 1995年10月托福阅读全真试题(1) |
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作者：佚名 文章来源：不详更新时间：2006-5-30 11:58:16  |
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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 in trees and other tall 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 cohesion (the attraction between
water molecules) are 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 7 is close
共9页: 1 [2] [3] [4] [5] [6] [7] [8] [9] 下一页
st in meaning to
(A) ignored
(B) showed
(C) disguised
(D) distinguished
4. What do the experiments mentioned in lines 7-9 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 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 16 refers to
(A) top
(B) tree
(C) water
(D) cohesion-tension theory.
8. The word "there" in line 18 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 24 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 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 30?
(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 water
13.Where in the passage does the author give an example of a plant with low root pressure?
(A) Lines3-4
(B) Lines5-7
(C) Lines10-11
(D) Lines12-13
Question 14-22
Mass transportation revised the social a
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nd 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, commuter trains, and
electric trolleys pulled settled regions outward two to four
times more distant from city centers than they were in the pre-
modern 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 fueled 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 million people.
Of course, many were never occupied; there was always
a huge surplus of subdivided, but vacant, land around Chicago
and other cities. These 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 land 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 a
共9页: 上一页 [1] [2] 3 [4] [5] [6] [7] [8] [9] 下一页
nd 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 commercial and residential districts.
(C) Changes in life in the inner city.
(D) Increasing standards of living.
16. The word "vast" in line 5 is closest in meaning to
(A) large
(B) basic
(C) new
(D) urban
17. The word "sparked" in line 15 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 23 is closest in meaning to
(A) certain
(B) popular
(C) improved
(D) possible
20. The word "many" in line 25 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.
Question 23-33
The preservation of embryos and juveniles is rare occurrence
in the fossil record. The tiny, delicate skeletons are usually
scattered by scavengers or destroyed by weathering before
they can be fossilized. Ichthyosaurs had a higher chance of
being preserved than did terrestrial creatures because, as marine
animals, they tende[1] [2] [3] 下一页
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