If the internal structure of a part is complex, the internal surfaces of it will result in

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第1题

The most notable surface fact about " The Waste Land" is of course its extreme disconnection. I do not know just how many parts the poem is supposed to have, but to me there are something like fifty parts which offer no bridges the one to the other and which are quite distinct in time, place, action, persons, tone and nearly all the unities to which art is accustomed. This discreteness reaches also to the inside of the parts, where it is indicated by a frequent want of grammatical joints and marks of punctuation; as if it were the function of art to break down the usual singleness of the artistic image, and then to attack the integrity of the individual fragments. I presume that poetry has rarely gone further in this direction. It is a species of the same error which modern writers of fiction practice when they laboriously disconnect the stream of consciousness and present items which do not enter into wholes. Evidently they think with Hume that reality is facts and pluralism, not compounds and systems. But Mr. Eliot is more enterprising than they, because almost in so many words he assails the philosophical or cosmical principles under which we form. the usual images of reality, naming the whole phantasmagoria Waste Land almost as plainly as if he were naming cosmos Chaos. His intention is evidently to present a wilderness in which both he and the reader may be bewildered, in which one is never to see the wood for the trees.

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第2题

TEXT C

The temperature of the Sun is over 5,000 degrees Fahrenheit at the surface, but it rises to perhaps more than 16 million degrees Fahrenheit at the center. The Sun is so much hotter than the Earth that matter can exist only as a gas, except at the core. In the core of the Sun, the pressures are so great against the gases that, despite the high temperature, there may be a solid core. However, no one really knows, since the center of the Sun can never be directly observed.

Solar astronomers do know that the Sun is divided into five layers or zones. Starting at the outside and going down into the Sun, the zones are the corona, chromosphere, photosphere, convection zone, and finally the core. The first three zones are regarded as the Sun's atmosphere. But since the Sun has no solid surface, it is hard to tell where the atmosphere ends and the main body of the Sun begins.

The Sun's outermost layer begins about 10,000 miles above the visible surface and goes outward for millions of miles. This is the only part of the Sun that can be seen during an eclipse such as the one in February 1979. At any other time, the corona can be seen only when special instruments are used on cameras and telescopes to shut out the glare of the Sun's rays.

The corona is a brilliant pearly white, filmy light, as bright as the full Moon. Its beautiful rays are a sensational sight during an eclipse. The corona's rays flash out in a brilliant fan that has wispy spike-like rays near the Sun's north and south poles. The corona is thickest at the Sun's equator.

The corona rays are made up of gases streaming outward at tremendous speeds and reaching a temperature of more than 2 million degrees Fahrenheit. The rays of gas thin out as they reach the space around the planets. By the time the Sun's corona rays reach the Earth, they are weak and invisible.

Matter on the Sun except at the core can exist only in the form. of gas because of the Sun's

[A] size.

[B] age.

[C] location.

[D] temperature.

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第3题

Asteroids and comets that repeatedly smashed into the early Earth covered the planet ’s surface with molten rock during its earliest days, but still may have left oases of water that could have supported the evolution of life, scientists say. The new study reveals that during the planet ’s infancy, the surface of the Earth was a hellish environment, but perhaps not as hellish as often thought, scientists added.

Earth formed about 4.5 billion years ago. The first 500 million years of its life are known as the Hadean Eon. Although this time amounts to more than 10 percent of Earth’s history, little is known about it, since few rocks are known that are older than 3.8 billion years old.

For much of the Hadean, Earth and its sister worlds in the inner solar system were pummeled with an extraordinary number of cosmic impacts. “It was thought that because of these asteroids and comets flying around colliding with Earth, conditions on early Earth may have been hellish, ” said lead study author Simone Marchi, a planetary scientist at the Southwest Research Institute in Boulder, Colorado. This imagined hellishness gave the eon its name —Hadean comes from Hades, the lord of the underworld in Greek mythology.

However, in the past dozen years or so, a radically different picture of the Hadean began to emerge. Analysis of minerals trapped within microscopiczircon crystals dating from this econ “suggested that there was liquid water on the surface of the Earth back then, clashing with the previous picture that the Hadean was hellish,” Marchi said. This could explain why the evidence of the earliest life on Earth appears during the Hadean —maybe the planet was less inhospitable during that eon than previously thought.

The exact timing and magnitude of the impacts that smashed Earth during the Hadean are unknown. To get an idea of the effects of this bombardment, Machi and his colleagues looked at the moon, whose heavily cratered surface helped model the battering that its close neighbor Earth must have experienced back then.

“We also looked at highly siderophile elements (elements that bind tightly to iron), such as gold, delivered to Earth as a result of these early collisions, and the amounts of these elements tells us the total mass accreted by Earth as the results of these collisions,”Marchi said. Prior research suggests these impacts probably contributed less than 0.5 percent of the Earth’s present-day mass. The researchers discovered that “the surface of the Earth during the Hadean was heavily affected by very large collisions, by impactors [ ?m&39;p?kt?] larger than 100 kilometers (60 miles) or so — really, really big impactors, ’ Marci said. “When Earth has a collision with an object that big, that melts a large volume of the Earth’s crust and mantle, covering a large fraction of the surface,” Marchi added. These findings suggest that Earth ’s surface was buried over and over again by large volumes of molten rock —enough to cover the surface of the Earth several times. This helps explain why so few rock survive from the Hadean, the researchers said.

Why is little known about the Earth ’s first 500 million years?

A.Because it is an imagined period of time.

B.Because this period is of little significance.

C.Because it is impossible to know about this period.

D.Because no rocks are available as research evidence.

Why is the early Earth imagined to be hellish?A.Because it was often smashed by asteroids and comets.

B.Because back then Hades, the lord of Hell, resigned.

C.Because it was so according to Greek mythology.

D.Because back then there was no life.

Why was the early Earth in fact less inhospitable than often thought?A.Because minerals of the Hadean have been found suggesting the existence of life.

B.Because the clashing brought by asteroids and comets was not completely damaging.

C.Because during the Hadean there already existed the evidence of life.

D.Because there had already been liquid water on the Earth back then.

How can the moon help with the understanding of the impacts that smashed the Earth?A.The moon once smashed into the Earth too.

B.The moon was battered earlier than the Earth.

C.The moon, as a close neighbor, is easier to observe.

D.The moon’s surface is heavily cratered as the Earth ’s.

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第4题

What produces a waterproof super glue, acts like a vacuum cleaner, and even teaches scientists about gene repair? The humble little shellfish known as the mussel (贻贝)。

Mussels are found worldwide. Some live in the sea. Others inhabit freshwater streams and lakes. When you try to move a mussel from a rock, you will discover what an incredibly firm grip it has a necessity if the mussel is to resist the sharp grab of a hungry seabird or the pounding waves of the sea. How does it manage to cling so tight? When it chooses a place to set up home, it pokes its tongue-shaped foot out of its shell and presses it against a solid surface. Special glands give off a fluid mixture of proteins into a channel that runs the length of the foot. The liquid quickly hardens into a fine, elastic thread about an inch long. Then a tiny pad-like structure at the end of this thread gives off some natural glue-like substance, the mussel lifts its foot, and anchor line number one is complete. These strategically placed threads form. a bundle, which ties the mussel to its new home in much the same way that ropes hold down a tent. The whole procedure takes only three or four minutes.

Imagine having a very strong glue that is non-toxic and so flexible that it can penetrate the tiniest holes and corners, sticking to any surface, even under water. Shipbuilders would welcome it for repairing vessels without the expense of dry-docking them. Auto-body workers would like a really waterproof paint that keeps the rust out. Surgeons would value a safe glue to join broken bones and to close wounds... The list of possible uses appears endless.

However, scientists are not thinking of using the mussels themselves to produce this super glue. It would take some l0.000 shellfish to make just one gram of glue. So collection enough mussels to supply the world's demand for super glue would wipe out the mussel population, many species of which are already endangered. Instead, American researchers have isolated and cloned the genes for five mussel glue proteins, and they are about to mass-produce them in the laboratory. However, the mussel is still one jump ahead. Only the mussel instinctively knows the exact blend of proteins needed for each kind of surface. Molecular biologist Frank Roberto has asked admiringly: "How are you ever going to imitate that?"

A mussel grips a hard surface very firmly to

A．seal itself from being damaged by sea water

B．protect itself from being the food of other animals

C．protect itself from being blown away by strong wind

D．produce the waterproof super glue

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第5题

The period of oscillation T of a water surface wave is assumed to be a function of density ρ,wavelength λ，depth h, gravity g, and surface tension γ. Rewrite this relationship in dimensionless form. What results if γ is negligible?

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第6题

The biosphere is the name biologists give to the sort of skin on the surface of this planet that is inhabitable by living organisms. Most land creatures occupy only the interface between the atmosphere and the land;birds extend their range for a few hundred feet into the atmosphere;burrowing invertebrates(无脊椎动物)such as earthworms may reach a few yards into the soil but rarely penetrate farther unless.it has been recently disturbed by men. Fish cover a wider range,from just beneath the surface of the sea to those depths of greater than a mile inhabited by specialized creatures. Fungi(真菌)and bacteria are plentiful in the atmosphere to a height of about half a mile,blown there by winds from the lower air. Balloon exploration of the stratosphere(同温层)as long ago as 1936 indicated that moulds and bacteria could be found at heights of several miles,recently the USAs National Aeronautics and Space Administration has detected them,in decreasing numbers,at heights up to eighteen miles. They arc pretty sparse at such levels, about one for every two thousand cubic feet, compared with 50 to 100 per cubic foot at two to six miles(the usual altitude of jet aircraft),and they are almost certainly in an inactive state. Marine bacteria have been detected at the bottom of the deep Pacific trench,sometimes as deep as seven miles; they are certainly not inactive. Living microbes have also been obtained on land from cores of rock drilled(while prospecting for oil)at depths of as much as 1,200 feet. Thus we can say, disregarding the exploits of astronauts, that the biosphere has a maximum thickness of about twenty-five miles. Active living processes occur only within a compass of about seven miles,in the sea, on land and in the lower atmosphere, but the majority of living creatures live within a zone of a hundred feet or so. If this planet were sealed down to the size of an orange,the biosphere,at its extreme width,would occupy the thickness of the orange-colored skin,excluding the pith. In this tiny zone of our planet takes place the multitude of chemical and biological activities that we call life. The way in which living creatures interact with each other, depend on each other or compete with each other, has fascinated thinkers since the beginning of recorded history. Living things exist in a fine balance which is often taken for granted, from a practical point of view, things could not be otherwise. Yet it is a source of continual amazement to scientists because of its intricacy and delicacy. The balance of nature is obvious most often when it is disturbed. Yet even here it can seem remarkable how quickly it readjusts itself to a new balance after a disturbance. The science of ecology—the study of the interaction of organisms with their environment—has grown up to deal with the minutiae of the balance of nature.

According to the passage,the"biosphere"is the layer on the earths surface_____.

A．where the atmosphere meets the sea

B．in which birds, fish and animals would die

C．in which plant and animal life can exist

D．in which earthworms and other invertebrates can live

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第7题

The Theory of Continental Drift has had a long and turbulent history since it was first proposed by Alfred Wegener in 1910. (46)Vigorously challenged yet widely ignored, the theory had languished for half a century, primarily due to its lack of a plausible mechanism to support the proposed drift. With the discovery of sea-floor spreading in the late 1950s and early 60s, the idea was reinvigorated. Plate tectonics is now almost universally accepted. Many details of the mechanism are to be worked out. The surface of the Earth is divided into approximately six large plates, plus a number of smaller ones. The plates are bounded by an interconnected network of ridges, transform. faults, and trenches. Ridges, also called spreading centers, occur where two plates are moving away from each Other. As the plates separate, hot molten mantle material flows up to fill the void. (47)The increased heat resulting from this flow reduces the density of the plates, causing them to float higher, thus elevating the boundaries by many thousands of feet above the colder surrounding sea floor. (48)Ridges on the ocean floor form. the longest continuous ranges of mountains on the planet, but only in a very few places on the Earth do these mountains rise above the ocean surface. New sea floor is constantly being created along spreading centers. Obviously somewhere else old sea floor must be going away. This occurs in trenches, also called subduction zones. Trenches occur along the boundary between two plates that are moving towards each other. (49)Where this occurs, one plate is bent downwards at about a 400 angle and plunges under the other plates leading edge, eventually to melt back into the liquid mantle below. As the subducting plate is heated back up to mantle temperatures, certain minerals in the plate melt sooner than others. (50)Minerals that melt at lower temperatures and are lighter than the surrounding material tend to rise, melting their way up through the overriding plate to erupt as volcanoes on the ocean floor. As these volcanoes grow, they rise above the ocean surface to form. lines of islands along the leading edge of the overriding plate. Numerous islands of Micronesia and Melanesia in the western Pacific were created in this way.

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第8题

SECTION B INTERVIEW

Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Questions 1 to 5 are based on an interview. At the end of the interview you will be given 10 seconds to answer each of the following five questions.

Now listen to the interview.

听力原文：Mr. Jones: What materials were used for road surfaces during the last century?

Engineer: Usually they were gravel and macadam. Tars and asphalt were originally used only as coverings, but later they were used as binders and finally as hot mixtures.

Mr. Jones: Concrete is a modern material as far as road - building goes, isn't it?

Engineer: Relatively speaking. But you might be surprised to know that a concrete road was built as early as 1893 in Ohio. But it was only 5 miles long. More extensive projects were not undertaken until much later, around 1912 or 1913.

Mr. Jones: This was because of the increase in traffic?

Engineer: That's right. Especially in the use of heavy tracks. More rigid pavements, such as concrete and brick, became a necessity. For light traffic, though, water-bound macadam, gravel, sand clay, and bituminous mixtures were still used.

Mr. Jones: What are turnpikes usually made of?

Engineer: Turnpikes are usually made of reinforced concrete about 8 to 10 inches thick, placed on a granular sub-base, which in turn is placed on a well - tacked earth subgrade. Of course, the construction depends a lot on the local climate, rainfall, soils, and so on.

Mr. Jones: How do you mean--climate?

Engineer: Frost is one of the main problems. For example, in Maine, where frost is quite frequent, the typical turnpike construction is a thin top layer of asphaltic concrete on a base layer of sand and gravel placed on a 36 - inch, frost - free, granular sub - grade.

Mr. Jones: What is the width of these roads?

Engineer: The early two - lane roads were about 20 feet wide. But with higher automobile speeds, the width requirements increased greatly. To give you an example, the Pennsylvania Turnpike has two 12 - foot lanes in each direction, separated by a median 10 feet wide. On each side there is a 10 - foot stabilized shoulder, marking a total width of 78 feet. The New Jersey Turnpike averages 100 feet in width, with three lanes in each direction.

Mr. Jones: I guess wider roads are being built every day.

Engrneer: That's right. Sometimes you think that, no matter how good a road you build, the speed and weight of vehicles will always be one step ahead.

What materials were not used for road surfaces during the last century?

A．Gravel.

B．Asphalt.

C．Macadam.

D．Concrete.

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第9题

SECTION B INTERVIEW

Now listen to the interview.

听力原文：Mr. Jones: What materials were used for road surfaces during the last century?

Engineer: Usually they were gravel and macadam. Tars and asphalt were originally used only as coverings, but later they were used as binders and finally as hot mixtures.

Mr. Jones: Concrete is a modem material as far as road building goes, isn't it?

Mr. Jones: This was because of the increase in traffic?

Engineer: That's fight. Especially in the use of heavy tracks. More rigid pavements, such as concrete and brick, became a necessity. For light traffic, though, water-bound macadam, gravel, sand clay, and bituminous mixtures were still used.

Mr. Jones: What are turnpikes usually made of?

Engineer: Turnpikes are usually made of reinforced concrete about 8 to 10 inches thick, placed on a granular sub-base, which in turn is placed on a well -tacked earth subgrade. Of course, the construction depends a lot on the local climate, rainfall, soils, and so on.

Mr. Jones: How do you mean--climate?

Mr. Jones: What is the width of these roads?

Engineer: The early two -lane roads were about 20 feet wide. But with higher automobile speeds, the width requirements increased greatly. To give you an ex-ample, the Pennsylvania Turnpike has two 12 -foot lanes in each direction, separated by a median 10 feet wide. On each side there is a 10 -foot stabilized shoulder, marking a total width of 78 feet. The New Jersey Turnpike averages 100 feet in width, with three lanes in each direction.

Mr. Jones: I guess wider roads are being built every day.

Engineer: That's right. Sometimes you think that, no matter how good a road you build, the speed and weight of vehicles will always be one step ahead.

What materials were not used for road surfaces during the last century?

A．Gravel.

B．Asphalt.

C．Macadam.

D．Concrete.

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