考博英语(阅读理解)历年真题试卷汇编5.doc

考博英语（阅读理解）历年真题试卷汇编5

(总分：38.00，做题时间：90分钟)

一、Reading Comprehensio(总题数：4，分数：38.00)

For 150 years scientists have tried to determine the solar constant, the amount of solar constant energy that reaches the Earth. Yet, even in the most cloud-free regions of the planet, the solar constant cannot be measured precisely. Gas molecules and dust particles in the atmosphere absorb and scatter sunlight and prevent some wavelengths of the light from ever reaching the ground. With the advent of satellites, however, scientists have finally been able to measure the Sun's output without being impeded by the Earth's atmosphere. Solar Max, a satellite from the National Aeronautics and Space Administration(NASA), has been measuring the Sun's output since February 1980. Although a malfunction in the satellite's control system limited its observation for a few years, the satellite was repaired in orbit by astronauts from the space-shuttle in 1984. Max's observations indicate that the solar constant is not really constant after all. The satellite's instruments have detected frequent, small variations in the Sun's energy output, generally amounting to no more than 0. 05 percent of the Sun's mean energy output and lasting from a few days to a few weeks. Scientists believe these fluctuations coincide with the appearance and disappearance of large groups of sunspots on the Sun's disk. Sunspots are relatively dark regions on the Sun's surface that have strong magnetic fields and a temperature about 2, 000 degrees Fahrenheit cooler than the rest of the Sun's surface. Particularly large fluctuations in the solar constant have coincided with sightings of large sunspot groups. In 1980, for example, Solar Max's instruments registered 0. 3 percent drop in the solar energy reaching the Earth. At that time a sunspot group covered about 0. 6 percent of the solar disk, an area 20 times larger than the Earth's surface. Long-term variations in the solar constant are more difficult to determine. Although Solar Max's data have indicated a slow and steady decline in the Sun's output, some scientists have thought that the satellite's aging detectors might have become less sensitive over the years, thus falsely indicating a drop in the solar constant. This possibility was dismissed, however, by comparing Solar Max's observations with data from a similar instrument operating on NASA's Nimbus 7 weather satellite since 1978.（分数：8.00）

(1).Why is it not possible to measure the solar constant accurately without a satellite?（分数：2.00）

A.the Earth is too far from the Sun.

B.Some areas on Earth receive more solar energy than others.

C.There is not enough sunlight during the day.

D.the Earth's atmosphere interferes with the sunlight.

(2).Why did scientists think that Solar Max might be giving unreliable information?（分数：2.00）

A.Solar Max did not work for the first few years.

B.Solar Max's instruments were getting old.

C.The space shuttle could not fix Solar Max's instruments.

D.Nimbus 7 interfered with Solar Max's detectors.

(3).The attempt to describe the solar constant can best be described as______.（分数：2.00）

A.an ongoing research effort

B.a question that can never be answered

C.an issue that has been resolved

D.historically interesting, but irrelevant to contemporary concerns

(4).What does this passage mainly discuss?（分数：2.00）

A.The components of the Earth's atmosphere.

B.The launching of a weather satellite.

C.The measurement of variations in the solar constant.

D.The interaction of sunlight and air pollution.

The human ear contains the organ for hearing and the organ for balance. Both organs involve fluid-filled channels containing hair cells that produce electrochemical impulses when the hairs are stimulated by moving fluid. The ear can be divided into three regions: outer, middle, and inner. The outer ear collects sound waves and directs them to the eardrum separating the outer ear from the middle ear. The middle ear conducts sound vibrations through three small bones to the inner ear. The inner ear is a network of channels containing fluid that moves in response to sound or movement. To perform the function of hearing, the ear converts the energy of pressure waves moving through the air into nerve impulses that the brain perceives as sound. Vibrating objects, such as the vocal cords of a speaking person, create waves in the surrounding air. These waves cause the eardrum to vibrate with the same frequency. The three bones of the middle ear amplify and transmit the vibrations to the oval window, a membrane on the surface of the cochlea, the organ of hearing. Vibrations of the oval window produce pressure waves in the fluid inside the cochlea. Hair cells in the cochlea convert the energy of the vibrating fluid into impulses that travel along the auditory nerve to the brain. The organ for balance is also located in the inner ear. Sensations related to body position are generated much like sensations of sound. Hair cells in the inner ear respond to changes in head position with respect to gravity and movement. Gravity is always pulling down on the hairs, sending a constant series of impulses to the brain. When the position of the head changes — as when the head bends forward — the force on the hair cells changes its output of nerve impulses. The brain then interprets these changes to determine the head's new position.（分数：10.00）

(1).What can be inferred about the organs for hearing and balance?（分数：2.00）

A.Both organs evolved in humans at the same time.

B.Both organs send nerve impulses to the brain.

C.Both organs contain the same amount of fluid.

D.Both organs are located in the ear's middle region.

(2).Hearing involves all of the following EXCEPT______.（分数：2.00）

A.motion of the vocal cords so that they vibrate.

B.stimulation of hair cells in fluid-filled channels.

C.amplification of sound vibrations.

D.conversion of wave energy into nerve impulses.

(3).It can be inferred from paragraphs 2 and 3 that the cochlea is a part of______.（分数：2.00）

A.the outer ear

B.the eardrum

C.the middle ear

D.the inner ear

(4).What can be inferred from paragraph 4 about gravity?（分数：2.00）

A.Gravity has an essential role in the sense of balance.

B.The ear converts gravity into sound waves in the air.

C.Gravity is a force that originates in the human ear.

D.The organ for hearing is not subject to gravity.

(5).What does "membrane" most probably mean?（分数：2.00）

A.member

B.part

C.thin cover

D.hole

The geology of the Earth's surface is dominated by the particular properties of water. Present on Earth in solid, liquid, and gaseous states, water is exceptionally reactive. It dissolves,

transports, and precipitates many chemical compounds and is constantly modifying the face of the Earth. Evaporated from the oceans, water vapor forms clouds, some of which are transported by wind over the continents. Condensation from the clouds provides the essential agent of continental erosion; rain. Precipitated onto the ground, the water trickles down to form brooks, streams, and rivers, constituting what is called the hydrographic network. This immense polarized network channels the water toward a single receptacle; an ocean. Gravity dominates this entire step in the cycle because water tends to minimize its potential energy by running from high altitudes toward the reference point that is sea level. The rate at which a molecule of water passes through the cycle is not random but is a measure of the relative size of the various reservoirs. If we define residence time as the average time for a water molecule to pass through one of the three reservoirs — atmosphere, continent, and ocean — we see that the times are very different. A water molecule stays, on an average, eleven days in the atmosphere, one hundred years on a continent and forty thousand years in the ocean. This last figure shows the importance of the ocean as the principal reservoir of the hydrosphere but also the rapidity of water transport on the continents.

A vast chemical separation process takes places during the flow of water over the continents. Soluble ions such as calcium, sodium, potassium, and some magnesium are dissolved and transported. Insoluble ions such as aluminum, iron, and silicon stay where they are and form the thin, fertile skin of soil on which vegetation can grow. Sometimes soils are destroyed and transported mechanically during flooding. The erosion of the continents thus results from two closely linked and interdependent processes, chemical erosion and mechanical erosion. Their respective interactions and efficiency depend on different factors.（分数：10.00）

(1).According to the passage, clouds are primarily formed by water______.（分数：2.00）

A.precipitating onto the ground

B.changing from a solid to a liquid state

C.evaporating from the oceans

D.being carried by wind

(2).The passage suggests that the purpose of the " hydrographic network" is to______.（分数：

2.00）

A.determine the size of molecules of water

B.prevent soil erosion caused by flooding

C.move water from the Earth's surface to the oceans

D.regulate the rate of water flow from streams and rivers

(3).What determines the rate at which a molecule of water moves through the cycle, as discussed in the third paragraph?（分数：2.00）

A.The potential energy contained in water.

B.The effects of atmospheric pressure on chemical compounds.

C.The amounts of rainfall that fall on the continents.

D.The relative size of the water storage areas.

(4).All of the following are examples of soluble ions EXCEPT______.（分数：2.00）

A.magnesium

B.iron

C.potassium

D.calcium

(5).The word "efficiency" in last sentence is closest in meaning to______.（分数：2.00）

A.relationship

B.growth

C.influence

D.effectiveness

Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hotels gravity pulls harder on the nearest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough. Scientists say this uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star's life, as it veered towards a supermassive black hole. When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. The new simulations investigated the effects of shock waves in detail, and found that even when their effects are included, the conditions favor a nuclear explosion. "There will be an explosion of the star — it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star's matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star's matter out of the black hole's reach, he says. The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Hatpern of Columbia University in New York, US2. " It may make it possible to see the disruption of that star immediately if it gets hot enough," he says. Brassart agrees. " Perhaps it can be observed in the X-rays and gamma rays, but it's something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US3, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process.（分数：10.00）

(1).Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage?（分数：2.00）

A.The black hole could tear apart the star.

B.The black hole could trigger a nuclear explosion in the star.

C.The black hole could dwindle its size considerably.

D.The black hole could devour the star.

(2).According to the third paragraph, researchers differed from each other in the problem of______.（分数：2.00）

A.whether nuclear reaction would occur.

B.whether the stars would increase its density and temperature.

C.whether shock waves would occur.

D.whether the uneven forces would flatten the stars.

(3).According to the fourth paragraph, which of the following is NOT true?（分数：2.00）

A.No nuclear explosion would be triggered inside the star.

B.The star would be destroyed completely.

C.Much of the star's matter thrown by the explosion would be beyond the black hole's reach.

D.The black hole would completely devour the star.

(4).What will happen several months after the explosion of the star?（分数：2.00）

A.The star's matter will move further away from by the black hole.

B.The black hole's matter will heat up.

C.The torn star's matter will swirl into the black hole.

D.The black hole's matter will release ultraviolet light and X-rays.

(5).According to the context, the word "disruption" in Paragraph 6 means______.（分数：2.00）

A.Confusion.

B.Tearing apart.

C.Interruption.

D.Flattening.