听力原文： Throughout history man has changed his physical environment in order to improve his way of life.
With the tools of technology he has altered many physical features of the earth. He has transformed wood lands into farmland, and made lakes and reservoirs out of rivers for irrigation purposes or hydroelectric power. Man has also modified the face of the earth by draining marshes and cutting through mountains to build roads and railways.
However, man's changes to the physical environment have not always had beneficial results. Today, pollution of the air and water is an increasing danger to the health of the planet. Each day thousands of tons of gases come out of the exhausts of motor vehicles; smoke from factories pollutes the air of industrialized areas and the surrounding areas of countryside. The air in cities is becoming increasingly unhealthy.
The pollution of water is equally harmful. In the sea, pollution from oil is increasing and is killing enormous numbers of algae ( a very simple plant without stems or leaves that grows in or near water), fish and birds. The whole ecological balance of the sea is being changed. The same problem exists in rivers, Industrial wastes have already made many rivers lifeless.
Conservationists believe that it is now necessary for man to limit the growth of technology in order to survive on earth.
(30)
A．Bettering his way of life.
B．Improving his surroundings.
C．Modifying the face of the planet.
D．Altering the physical features of the earth.
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In ________ times human beings did not travel for pleasure but to find a more favourable climate.
A) prime
B) primitive
C) primary
D) preliminary
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A．In Boston.
B．in Concord.
C．In Lexington.
D．In Britain.
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The fact that they reacted so differently was a reflection of their different ________.
A) performances
B) personalities
C) qualities
D) appearances
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Minority Report
American universities are accepting more minorities than ever. Graduating them is another matter.
Barry Mills, the president of Bowdoin College, was justifiably proud of Bowdoin's efforts to recruit minority students. Since 2003 the small, elite liberal arts school in Brunswick, Maine, has boosted the proportion of so-called under-represented minority students in entering freshman classes from 8% to 13% . "It is our responsibility to reach out and attract students to come to our kinds of places," he told a NEWSWEEK reporter. But Bowdoin has not done quite as well when it comes to actually graduating minorities. While 9 out of 10 white students routinely get their diplomas within six years, only 7 out of 10 black students made it to graduation day in several recent classes.
"If you look at who eithers college, it now looks like America," says Hilary Pennington, director of postsecondary programs for the Bill & Melinda Gates Foundation, which has closely studied enrollment patterns in higher education. " But if you look at who walks across the stage for a diploma, it's still largely the white, upper-income population.
The United States once had the highest graduation rate of any nation. Now it stands 10th. For the first time in American history, there is the risk that the rising generation will be less well educated than the previous one. The graduation rate among 25-to 34-year-olds is no better than the rate for the 55-to 64-year-olds who were going to college more than 30 years ago. Studies show that more and more poor and non-white students want to graduate from college— but their graduation rates fill far short of their dreams. The graduation rates for blacks, Latinos, and Native Americans lag far behind the graduation rates for whites and Asians. As the minority population grows in the United States, low college graduation rates be some a threat to national prosperity.
The problem is pronounced at public universities. In 2007 the University of Wisconsin-Madison—one of the top five or so prestigious publi 3 universities—graduated 81 % of its white students within six years, but only 56% of its blacks. At less-selective slate schools, the numbers get worse. During the same time frame, the University of Northern Iowa graduated 67% of its white students, but only 39% of its blacks. Community colleges have low graduation rates generally—but rock-bottom rates for minorities. A recent review of California community colleges found that while a third of the Asian students picked up their degrees, only 15% of African-Americans did so as well.
Private colleges and universities generally do better, partly because they offer smaller classes and more personal attention. But when it cones to a significant graduation gap, Bowdoin has company. Nearby Colby College logged an 18-point difference between white and black graduates in 2007 and 25 points in 2006. Middlebury College in Vermont, another top school, had a 19-point gap in 2007 and a 22-point gap in 2006. The most selective private schools— Harvard, Yale, and Princeton—show almost no gap between black and white graduation rates. But that may have more to do with their ability to select the best students. According to data gathered by Harvard Law School professor Lani Guinier, the most selective schools are more likely to choose blacks who have at least one immigrant parent from Africa or the Caribbean than black students who are descendants of American slaves.
" Higher education has been able to duck this issue for years, particularly the more selective schools, by saying the responsibility is on the individual student," says Pennington of the Gates Foundation. "If they fail, it's their fault. " Some critics blame affirmative action-students admitted with lower test scores and grades from shaky high schools often struggle at elite schools. But a bigger problem m
A．The small proportion of minority students.
B．The low graduation rates of minority students.
C．The growing conflicts among ethnic groups.
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If our solar system has a Hell, it's Venus. The air is choked with foul and corrosive sulfur, heaved from ancient volcanoes and feeding acid clouds above. Although the second planet is a step farther from the sun than Mercury, a runaway greenhouse effect makes it hotter indeed. It's the hottest of the nine plants, a toasty 900 degrees Fahrenheit of baking rocky flats from equator to poles. All this under a crushing atmospheric pressure 90 times that of where you're sitting now. From the earthly perspective, a dead end. It must be lifeless.
"Venus has nothing," is the blunt word from planetologist Kevin Zahnle of NASA Ames Research Center in Calitfornia's Silicon Valley. "We've written it off."
Yet a small group of advanced life-forms on Earth begs to differ, and theorizes that bizarre microbial ecosystems might have once populated Venus and, in fact, may be there still. Members of this loose band of researchers suggest that their colleagues have water too much on the brain, and are, in a sense, H2O chauvinists (盲目的爱国者).
"Astrobiologists are neglecting Venus due more to narrow thinking than actual knowledge of the environment, or environments, where life can thrive," says Dirk Schulze-Makuch, a geobiologist at the University of Texas at E1 Paso who recently co-authored a Venus-boosting paper in Astrobiology with colleague Louis Irwin.
The bias against life on Venus is partly rooted in our own biology. Human experience instructs that liquid water, preferably lot of it, is essential for life. In search for extraterrestrial life, we obsess over small rivers in Mars' surface apparently carved by ancient gushes of water, and delight in hints of permafrost (永久冻结带) just underneath its surface. (By comparison, Venus isn't even that interesting to look at: A boring cue ball (台球的白色母球) for backyard astronomers, its clouds reflects 75% of visible light.) Attention and then funding follow the water: Three more landers will depart for Mars this spring, and serious plans for sample-return missions hover in the midterm future.
"If you have limited resources, you base exploration on what you know," says Arizona State University planetary geologist Ronal Greeley. It's like losing your keys on the way home at night: The first place you look is under the streetlights not because they're more likely to be there, but because if they are, you'll spot them. For astrobiologists, the streetlights are the spectral (光谱的)lines for water, and they've spotted that potential on Mars, Jupiter's moon Europa, even Neptune's moon Triton. Not on the baking rocky flats of Venus.
Venus is the hottest of all the nine planets in the solar system because______.
A．it is not so close to the Sun as Mercury
B．many volcanoes spread the whole planet
C．it is covered by a thick layer of cloud
D．greenhouse effect is uncontrollable on it