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 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. 【題組】
1. How many theories does the author mention?
2.【題組】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?
4.【題組】4. What do the experiments mentioned in lines 5-7 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.【題組】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.【題組】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.
11.【題組】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.【題組】12.Why does the author mention steel wire in line 22?
(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
14. 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 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.
【題組】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.【題組】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.
18.【題組】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.
21.【題組】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.【題組】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.
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 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 if 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 specimens 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 20 and 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 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.
【題組】23. The passage supports which of the following conclusions?
(A) Some species of ichthyosaurs decayed more rapidly than other species.
(B) Ichthyosaur newborns are smaller than other newborn marine reptiles.
(C) Ichthyosaurs were more advanced than terrestrial creatures.
(D) Ichthyosaurs may have gathered at Holzmaden to give birth.
25.【題組】25. All of the following are mentioned as factors that encourage fossilization EXCEPT the
(A) speed of burial
(B) conditions of the water
(C) rate at which soft tissues decay
(D) cause of death of the animal.
26.【題組】26. Which of the following is true of the fossil deposits discussed in the passage?
(A) They include examples of newly discovered species.
(B) They contain large numbers of well-preserved specimens
(C) They are older than fossils found in other places
(D) They have been analyzed more carefully than other fossils.
29.【題組】29. Why does the author mention the specimen preserved in the birth canal (line 19)?
(A) To illustrate that the embryo fossils are quite advanced in their development
(B) To explain why the fossils are well preserved
(C) To indicate how the ichthyosaurs died
(D) To prove that ichthyosaurs are marine animals.
32.【題組】32.Which of the following best expresses the relationship between the first and second paragraphs?
(A) The first paragraph describes a place while the second paragraph describes a field of study.
(B) The first paragraph defines the terms that are used in the second paragraph.
(C) The second paragraph describes a specific instance of the general topic discussed in the first paragraph.
(D) The second paragraph presents information that contrasts with the information given in the first paragraph.
The Lewis and Clark expedition, sponsored by President Jefferson, was the most important official examination of the high plains and the Northwest before the War of 1812. The President's secretary, Captain Meriwether Lewis, had been instructed to "explore the Missouri River, and such principal streams of it as, by its course and communication with the waters of the Pacific Ocean …may offer her most direct and practicable water communication across the continent, for the purposes of commerce." Captain William Clark, the younger brother of famed George Rogers Clerk, was invited to share the command of the exploring party.
Amid rumors that there were prehistoric mammoths wandering around the unknown region and that somewhere in its wilds was a mountain of rock salt 80 by 45 miles in extent, the two captains set out. The date was May 14, 1804. Their point of departure was the mouth of the Wood River, just across the Mississippi from the entrance of the Missouri River. After toiling up the Missouri all summer, the group wintered near the Mandan villages in the center of what is now North Dakota. Resuming their journey in the spring of 1805, the men worked their way along the Missouri to its source and then crossed the mountains of western Montana and Idaho. Picking up a tributary of the Columbia River, they continued westward until they reached the Pacific Ocean, where they stayed until the following spring.
Lewis and Clark brought back much new information, including the knowledge that the continent was wider than originally supposed. More specifically, they learned a good deal about river drainages and mountain barriers. They ended speculation that an easy coast-to-coast route existed via the Missouri-Columbia River systems, and their reports of the climate, the animals and birds, the trees and plants, and the Indians of the West – though not immediately published – were made available to scientists.
【題組】34.With what topic is the passage primarily concerned?
(A) The river systems of portions of North America.
(B) Certain geological features to the North American continent.
(C) An exploratory trip sponsored by the United States government.
(D) The discovery of natural resources in the United States.
35.【題組】35.According to the passage, the primary purpose of finding a water route across the continent was to
(A) gain easy access to the gold and other riches of the Northwest
(B) become acquainted with the inhabitants of the West.
(C) investigate the possibility of improved farmland in the West.
(D) facilitate the movement of commerce across the continent
38.【題組】38.The author states that Lewis and Clark studied all of the following characteristics of the explored territories EXCEPT
(A) mineral deposits
(B) the weather
(C) animal life
(D) native vegetation
40.【題組】40.It can be inferred from the passage that prior to the Lewis and Clark expedition the size of the continent had been
(A) of little interest
(C) known to native inhabitants of the West
(D) unpublished but known to most scientists
For a century and a half the piano has been one of the most popular solo instruments for Western music. Unlike string and wind instrument, the piano is completely self-sufficient, as it is able to play both the melody and its accompanying harmony at the same time. For this reason, it became the favorite household instrument of the nineteenth century.
The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centu
ries – the spinet, the dulcimer, and the virginal. In the seventeenth century the organ, the clavichord, and the harpsichord became the chief instruments of the keyboard group, a supremacy they maintained until the piano supplanted them at the end of the eighteenth century. The clavichord's tone was metallic and never powerful; nevertheless, because of the variety of tone possible to it, many composers found the clavichord a sympathetic instrument for concert use, but the character of the tone could not be varied save by mechanical or structural devices.
The piano was perfected in the early eighteenth century by a harpsichord maker in Italy (though musicologists point out several previous instances of the instrument). This instrument was called a piano e forte(soft and loud), to indicate its dynamic versatility; its strings were struck by a recoiling hammer with a felt-padded head. The wires were much heavier in the earlier instruments. A series of mechanical improvements continuing well into the nineteenth century, including the introduction of pedals to sustain tone or to soften it, the perfection of a metal frame and steel wire of the finest quality, finally produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound, from a liquid, singing tone to a sharp, percussive brilliance.
【題組】42. What does the passage mainly discuss?
(A) The historical development of the piano
(B) The quality of tone produced by various keyboard instruments
(C) The uses of keyboard instruments in various types of compositions
(D) The popularity of the piano with composers
49.【題組】49. According to the information in the third paragraph, which of the following improvements made it possible to lengthen the tone produced by the piano?
(A) The introduction of pedals
(B) The use of heavy wires
(C) The use of felt-padded hammerheads
(D) The metal frame construction