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TOEFL全真试题（2-2） |
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| 作者：佚名 来源：互联网 点击数： 更新时间：2006-6-30
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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 , the
movement 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
[6] [7] [8] [NextPage]
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 out people 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 million
people.
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
[6] [7] [8] [NextPage]
(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
Questions 23-33
The preservation of embryos and juveniles is a rate 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 tended to live
in environments less subject to erosion. Still, their fossilization required a suite
of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack
of swift currents and waves to jumble and carry away small bones, and fairly rapid
burial. Given these factors, some areas have become a treasury of well-preserved
ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The
ichthyosaur remains are found in black , bituminous marine shales deposited about
190 million years ago. Over the years, thousands of speciments of marine reptiles, fish,
and invertebrates have been recovered from these rocks. The quality of preservation is
outstanding, but what is even more impressive is the number of ichthyosaur fossils
containing preserved embryos. Ichthyosaurs with embryos have been reported from 6
different levels of the shale in a small area around Holzmaden, suggesting that a
specific site was used by large numbers of ichthyosaurs repeatedly over time.The
embryos are quite advanced in their physical development; their paddles, for example,
are already well formed. One specimen is even preserved in the birth canal. In addition,
the shale contains the remains of many newborns that are between 20and 30 inches
long.
Why are there so many pregnant females and young at Holzmaden when they are so
rare elsewhere? The quality of preservation, is almost unmatched and quarry operations
have been carried out carefully with an awareness of the value of the fossils. But these
factors do not account for the interesting question of how there came to be such a
concentration of pregnant ichthyosaurs in a particular place very close to their time of
giving birth.
23.The passage supports which of the following conclusions?
(A) Some species of ichthyoeaurs decayed more rapidly than other species.
(B) Ichthyosaur newborns are smaller than other new born inarine reptiles.
(C) Ichthyosaurs were more advanced than terrestrial creatures.
[6] [7] [8] |
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上一篇考试资料： TOEFL全真试题（1-2）
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