When Jules Verne wrote Journey to the Center of the Earth in 1864, there were many conflicting theories about the nature of the Earth's interior. Some geologists thought that it contained a highly compressed ball of incandescent gas, while others suspected that it consisted of separate shells, each made of a different material. Today, well over a century later, there is still little direct evidence of what lies beneath our feet. Most of our knowledge of the Earth's interior comes not from mines or boreholes, but from the study of seismic waves - powerful pulses of energy released by earthquakes.
The way that seismic waves travel shows that the Earth's interior is far from uniform. The continents and the seabed are formed by the crust - a thin sphere of relatively light, solid rock. Beneath the crust lies the mantle, a very different layer that extends approximately halfway to the Earth's center. There the rock is the subject of a battle between increasing heat and growing pressure.
In its high levels, the mantle is relatively cool; at greater depths, high temperatures make the rock behave more like a liquid than a solid. Deeper still, the pressure is even more intense, preventing the rock from melting in spite of a higher temperature.
Beyond a depth of around 2,900 kilometers, a great change takes place and the mantle gives way to the core. Some seismic waves cannot pass through the core and others are bent by it. From this and other evidence, geologists conclude that the outer core is probably liquid, with a solid center. It is almost certainly made of iron, mixed with smaller amounts of other elements such as nickel.
The conditions in the Earth's core make it a far more alien world than space. Its solid iron heart is subjected to unimaginable pressure and has a temperature of about 9,000oF. Although scientists can speculate about its nature, neither humans nor machines will ever be able to visit it. 【題組】
1. The word "conflicting" in line 2 is closest in meaning to
4.【題組】4. Which of the following is a primary characteristic of the Earth's mantle?
(A) Light, solid rock
(B) Uniformity of composition
(C) Dramatically increasing pressure
(D) Compressed, incandescent gas
7.【題組】7. Why does the author state in line 22 that the Earth's core is "more alien" than space?
(A) Government funds are not available to study the Earth's core.
(B) Scientists aren't interested in the characteristics of the Earth's core.
(C) It is impossible to go to the Earth's core to do research.
(D) The Earth's core is made of elements that are dangerous to humans.
Despite the road improvements of the turnpike era (1790-1830). Americans continued as in colonial times to depend wherever possible on water routes for travel and transportation. The larger rivers, especially the Mississippi and the Ohio, became increasingly useful as steamboats grew in number and improved in design.
River boats carried to New Orleans the corn and other crops of northwestern farmers, the cotton and tobacco of southwestern planters. From New Orleans, ships took the cargoes on to eastern seaports. Neither the farmers of the west nor the merchants of the east were completely satisfied with this pattern of trade. Farmers could get better prices for their crops if the alternative existed of sending them directly eastward to market and merchants could sell larger quantities of their manufactured goods if these could be transported more directly and more economically to the west.
New waterways were needed. Sectional jealousies and constitutional scruples stood in the way of action by the federal government and necessary expenditures were too great for private enterprise. If extensive canals were to be dug, the job would be up to the various states.
New York was the first to act. It had the natural advantage of a comparatively level route between the Hudson River and Lake Erie, through the only break in the entire Appalachian Mountain chain. Yet the engineering tasks were imposing. The distance was more than 350 miles and there were ridges to cross and a wilderness of woods and swamps to penetrate. The Erie Canal begun in 1817 and completed in 1825, was by far the greatest construction job that Americans had ever undertaken. It quickly proved a financial success as well. The prosperity of the Erie encouraged the state to enlarge its canal system by building several branches.
The range of the New York canal system was still further extended when the states of Ohio and Indiana, inspired by the success of the Erie Canal, provided water connections between Lake Erie and the Ohio River.
【題組】9. What does the passage suggest was the principal route for transporting crops to the east prior in 1825?
(A) River to road
(B) Canal to river
(C) River to ocean
(D) Road to canal.
10.【題組】10. It can be inferred from the passage that shipping cargo east by way of New Orleans was
(A) Advantageous for manufactures
(B) Inexpensive for merchants
(C) Not economical for farmers
(D) Considered economical by the government
14.【題組】14. According to the passage, where was the Erie Canal located?
(A) Between Ohio and Indiana.
(B) Along the Appalachian Mountains
(C) Between Lake Erie and the Ohio River
(D) Across New York State.
19.【題組】19. According to the passage, Indiana and Ohio supported the development of the New York canal system by
(A) helping to build the Erie Canal.
(B) Building branches to connect it with the Ohio River
(C) Providing much of the water for the Erie Canal.
(D) Contributing financially to the construction costs
20.【題組】20. What does the paragraph following the passage probably discuss?
(A) Industry on Lake Erie
(B) Canals in Ohio and Indiana
(C) Sectional jealousies in Indiana and Ohio
(D) Travel on the Erie Canal.
Legend has it that sometime toward the end of the Civil War (1861-1865) a government train carrying oxen traveling through the northern plains of eastern Wyoming was caught in a snowstorm and had to be abandoned. The driver returned the next spring to see what had become of his cargo. Instead of the skeletons he had expected to find, he saw his oxen, living, fat, and healthy. How had they survived?
The answer lay in a resource that unknowing Americans lands trampled underfoot in their haste to cross the "Great American Desert" to reach lands that sometimes proved barren. In the eastern parts of the United States, the preferred grass for forage was a cultivated plant. It grew well with enough rain, then when cut and stored it would cure and become nourishing hay for winter feed. But in the dry grazing lands of the West that familiar bluejoint grass was often killed by drought. To raise cattle out there seemed risky or even hopeless.
Who could imagine a fairy-tale grass that required no rain and somehow made it possible for cattle to feed themselves all winter? But the surprising western wild grasses did just that. They had wonderfully convenient features that made them superior to the cultivated eastern grasses. Variously known as buffalo grass, grama grass, or mesquite grass, not only were they immune to drought; but they were actually preserved by the lack of summer and autumn rains. They were not juicy like the cultivated eastern grasses, but had short, hard stems. And they did not need to be cured in a barn, but dried right where they grew on the ground. When they dried in this way, they remained naturally sweet and nourishing through the winter. Cattle left outdoors to fend for themselves thrived on this hay. And the cattle themselves helped plant the fresh grass year after year for they trampled the natural seeds firmly into the soil to be watered by the melting snows of winter and the occasional rains of spring. The dry summer air cured them much as storing in a barn cured the cultivated grasses.
【題組】21. What does the passage mainly discuss?
(A) Western migration after the Civil War
(B) The climate of the western United States
(C) The raising of cattle.
(D) A type of wild vegetation
22.【題組】22. What can be inferred by the phrase "Legend has it" in line 1?
(A) The story of the train may not be completely factual.
(B) Most history books include the story of the train.
(C) The driver of the train invented the story.
(D) The story of the train is similar to other ones from that time period.
24.【題組】24. What can be inferred about the "Great American Desert" mentioned in line 7?
(A) It was not originally assumed to be a fertile area.
(B) Many had settled there by the 1860's.
(C) It was a popular place to raise cattle before the Civil War.
(D) It was not discovered until the late 1800's.
27.【題組】27. Which of the following can be inferred about the cultivated grass mentioned in the second paragraph?
(A) Cattle raised in the western United States refused to eat it.
(B) It would probably not grow in the western United States.
(C) It had to be imported into the United States.
(D) It was difficult for cattle to digest.
29.【題組】29. Which of the following was NOT mentioned as a characteristic of western grasses?
(A) They have tough stems.
(B) They are not affected by dry weather.
(C) They can be grown indoors.
(D) They contain little moisture.
31.【題組】31. According to the passage, the cattle helped promote the growth of the wild grasses by
(A) stepping on and pressing the seeds into the ground
(B) naturally fertilizing the soil
(C) continually moving from one grazing area to another
(D) eating only small quantities of grass.
Seventeenth-century houses in colonial North America were simple structures that were primarily functional carrying over traditional designs that went back to the Middle Ages. During the first half of the eighteenth century, however, houses began to show a new elegance. As wealth increased, more and more colonists built fine houses.
Since architecture was not yet a specialized profession in the colonies, the design of buildings was left either to amateur designers or to carpenters who undertook to interpret architectural manuals imported from England. Inventories of colonial libraries show an astonishing number of these handbooks for builders, and the houses erected during the eighteenth century show their influence. Nevertheless, most domestic architecture of the first three-quarters of the eighteenth century displays a wide divergence of taste and freedom of application of the rules laid down in these books.
Increasing wealth and growing sophistication throughout the colonies resulted in houses of improved design, whether the material was wood, stone, or brick. New England still favored wood, though brick houses became common in Boston and other towns, where the danger of fire gave an impetus to the use of more durable material. A few houses in New England were built of stone, but only in Pennsylvania and adjacent areas was stone widely used in dwellings. An increased use of brick in houses and outbuildings is noticeable in Virginia and Maryland, but wood remained that most popular material even in houses built by wealthy landowners. In the Carolinas, even in closely packed Charleston, wooden houses were much more common than brick houses.
Eighteenth-century houses showed great interior improvements over their predecessors. Windows were made larger and shutters removed. Large, clear panes replaced the small leaded glass of the seventeenth century. Doorways were larger and more decorative. Fireplaces became decorative features of rooms. Walls were made of plaster or wood, sometimes elaborately paneled. White paint began to take the place of blues, yellows, greens, and lead colors, which had been popular for walls in the earlier years. After about 1730, advertisements for wallpaper styles in scenic patterns began to appear in colonial newspapers.
【題組】32. What does the passage mainly discuss?
(A) The improved design of eighteenth-century colonial houses.
(B) A comparison of eighteenth-century houses and modern houses.
(C) The decorations used in eighteenth-century houses.
(D) The role of carpenters in building eighteenth-century houses.
33.【題組】33. What was one of the main reasons for the change in architectural style in eighteenth-century North America?
(A) More architects arrived in the colonies.
(B) The colonists developed an interest in classical architecture.
(C) Bricks were more readily available.
(D) The colonists had more money to spend on housing.
40.【題組】40. The word "predecessors" in line 23 refers to
(A) colonist who arrived in North America in the seventeenth century.
(B) houses constructed before the eighteenth century
(C) interior improvements
(D) wooden houses in Charleston
41.【題組】41. The author mentions elaborately paneled walls in line 26 as an example of
(A) how the interior design of colonial houses was improved.
(B) why walls were made of wood or plaster.
(C) How walls were made stronger in the eighteenth century.
(D) What kind of wood was used for walls after 1730.
43.【題組】43. What does the author imply about the use of wallpaper before 1730?
(A) Wallpaper samples appeared in the architectural manuals.
(B) Wallpaper was the same color as the wall paints used
(C) Patterned wallpaper was not widely used.
(D) Wallpaper was not used in stone house.
Bloodhounds are biologically adapted to trailing their prey. The process by which the nose recognizes an odor is not fully understood, but there are apparently specific receptor sites for specific odors. In one explanation, recognition occurs when a scent molecule fits into its corresponding receptor site, like a key into a lock, causing a mechanical or chemical change in the cell. Bloodhounds apparently have denser concentrations of receptor sites tuned to human scents.
When a bloodhound trails a human being, what does it actually smell? The human body, which consists of about 60 trillion living cells, sheds exposed skin at a rate of 50 million cells a day. So even a trail that has been dispersed by breezes may still seem rich to a bloodhound. The body also produces about 31 to 50 ounces of sweat a day. Neither this fluid nor the shed skin cells have much odor by themselves, but the bacteria working on both substances is another matter. One microbiologist estimates the resident bacteria population of a clean square centimeter of skin on the human shoulder at "multiples of a million." As they go about their daily business breaking down lipids, or fatty substances, on the skin, these bacteria release volatile substances that usually strike the bloodhound's nose as an entire constellation of distinctive scents.
【題組】45. What does the passage mainly discuss?
(A) Why people choose bloodhounds for household pets
(B) How a bloodhound's sense of smell works
(C) How humans compensate for an underdeveloped sense of smell
(D) The way in which bacteria work on skin cells and body sweat.
49.【題組】49. In line 10, the word "rich" is used to mean that a trail is
(A) paved with precious materials
(B) a profitable business to get into
(C) a very costly undertaking
(D) filled with an abundance of clues.