[单项选择]According to the passage, scientists have decided that sulfur aerosols from volcanic eruptions affect global temperatures to a greater extent than ash clouds because
A. the greenhouse gas effect produced by human activities tends to have a much greater environmental effect than that of volcanic explosions
B. clouds of sulfur-rich gases tend to achieve greater heights in the stratosphere than do ash clouds
C. a particular explosion producing high sulfur and little ash had a greater environmental effect than the converse
D. the burning of fossil fuels tends to exacerbate the effects of sulfurous aerosols, but not those of ash clouds
E. global warming effects tend to minimize the impact of ash clouds, but not those of sulfurous aerosols

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[单项选择]Passage Six

Scientists have known for more than two decades that cancer is a disease of the genes. Something scrambles the DNA inside a nucleus, and suddenly, instead of dividing in a measured fashion, a cell begins to copy itself furiously. Unlike an ordinary cell, it never, stops. But describing the process isn’t the same as figuring it out. Cancer cells are so radically different from normal ones that it’s almost impossible to untangle the sequence of events that made them that way. So for years researchers have been attacking the problem by taking normal cells and trying to determine what changes will turn them cancerous - always Without success.
According to a report in the current issue of Nature, a team of scientists based at M. I .T.’s Whitehead Institute for Biomedical Research has finally managed to make human ceils malignant -a f
A. to subject them to two more genes
B. to keep the division from slowing down
C. to promote the production of telomerase
D. to prevent excessive ceils copying

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[填空题]Passage Ten Scientists have been finding evidence of life inside meteorites for well over 100 years — that, or the building blocks of life. The claims of life have proved false every time. It always turns out to be a wishful interpretation of chemicals, minerals and tiny structures inside the meteorite that could be the fossilized long-dead bacteria — but almost certainly aren’t.

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[单项选择]According to the passage, why haven’t scientists found a cure for the common cold（）
A. They haven’t devoted as much energy to medicine as to space travel.
B. There are too many kinds of cold viruses for them to identify.
C. It is not economical to find a cure for each type of cold.
D. They believe people can recover without treatment.

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[单项选择]Passage Two

Have you ever been startled by a loud noise or by someone appearing suddenly behind you on dark night or by a snake in the grass Do you remember the sudden, tight feeling in your chest, the way your heart started go pound, the way you seemed to breathe more rapidly Such reactions occurred because you were frightened. Your brain sent a signal to the special gland (腺) in your body caned the adrenal (肾上的) gland. Other parts of your body were involved, too, but the adrenal gland has a very special function.
The adrenal gland is located on top of your kidney. Since you have two kidneys. You also have two adrenal glands. Each adrenal gland is divided into two parts: a cortex (外皮) and a medulla (髓质). The cortex forms the outer shell; the medulla forms the central core. Both the cortex and the medulla secrete (分泌) hormones, but they hav
A. the human brain
B. glands and systems in the body
C. the cortex of the adrenal gland
D. the medulla of the adrenal gland

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[单项选择]Passage One 　　Have you ever dreamed of visiting a planet in the Milk Way While the trip sounds exciting, it would take years and years to reach your destination. So in the future, bedtime for astronauts may be more than a few hours of regular shut-eye. They would have to sleep for years. 　　European researchers are now conducting hibernation experiments. The study may help them understand whether humans could ever sleep through the years it would take for a space flight to distant planets. “If there was an effective technology, it could make deep-space travel a reality,” said Mark Ayre of the European Space Agency last month. 　　What seems like science fiction is not completely unlikely. Researchers have been able to use chemicals to put living cells into a sleep-like state where they don’t age. They have now moved on to small, non-hibernating mammals like rats. The results will be out by the end of 2009. 　　A major challenge is the fact that cells can be very simple systems, wher
A. ensure astronauts to get a complete sleep
B. find the secret of some creatures
C. make preparations for the journey to Jupiter’s moon Callisto
D. know if man can sleep for years

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[单项选择]Passage Four Have you ever been afraid to talk back when you were treated unfairly Have you ever bought something just because the salesman talked you into it Are you afraid to ask someone for a date Many people are afraid to assert themselves (坚持已见). Dr. Robert Alberti, author of Stand Up, Speak Out, and Talk Back, thinks it’s because of their lack of confidence. "Our structure of organization tends to make people distrust themselves," says Alberti. "There’s always a ’superior’ around—a parent, a teacher, a boss—who knows better’. These ’superiors’ often gain when they keep breaking at your self-image." But Alberti and other scientists are doing something to help people assert themselves. They offer "assertiveness training" courses—AT for short. In the AT course people learn that they have a right to be themselves. They learn to speak out and feel good about doing so. They learn to be aggressive without hurting people. In one way, learning to speak out is to overc
A. they have a poor self-image
B. they have not received AT courses
C. they have not grasped communication skills
D. they are not generous enough to share things

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[简答题]Scientists at Johns Hopkins have discovered "striking" differences between men and women in a part of the brain linked with ability to estimate time, judge speed, visualize things three-dimensionally and solve mathematical problems.
47)The differences, the researchers say, may underlie well-known trends that vary by sex, such as the fact that more men than women are architects, mathematicians and race-car drivers.
In a study reported this week in the Journal Cerebral Cortex, the researchers show that a brain region called the inferior parietal lobule is significantly larger overall in men than in women. The area is part of the cerebral cortex and appears on both sides of the brain just above ear-level.
Also, there’s a symmetry difference, with men having a larger left IPL than right. 48) In women in the study, it’s the right IPL that’s somewhat larger, though the difference between the two sides of the brain is less obvious than in men, says psychiatrist

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