单项选择题A good deal of research is being carried out nowadays () the cause of juvenile crime.It is obvious that one of these is an unsatisfactory home background.

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3.If our solar system has a Hell. it&39;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 sunthan Mercury, a runaway greenhouse effect makes it hotter indeed. It&39;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&39;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 California&39;s Silicon Valley. "We&39;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 io 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 El Paso who recently co-authored a Venus-boosting paper in Astrobiology wich colleague Louis Irwin.
The bias against life on Venus is partly rooted in our own biology. Human experience instructs that liquidwater, preferably lot of it. is essential for life. In search for extraterrestrial life, we obsess over small rivers in Mars&39; 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&39;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&39;s like losing your keys on the way home al night: The first place you look is under the streetlights not because they&39;re more likely to be there. but because if they are. you’llspot them. For astrobiologists. the streetlights are the spectral (光谱的) lines for water. and they&39;ve spotted that potential on Mars, Jupiter&39;s moon Europa. even Neptune&39;s moon Triton. Not on the baking rocky flats of Venus.
测试题
Venus is the hottest of all the nine planets in the solar system because_____________.

A.it
J.many
K.it
L.greenhouse

4.If you go down to the woods today, you may meet high-tech trees genetically modified to speed their growthor improve the quality of their wood. Genetically-engineered food crops have become increasingly common, albeit controversial. over the past ten years. But genetic engineering of trees has lagged behind.
Part of the reason is technical. Understanding. and then altering, the genes of a big pine tree are more complex than creating a better tomato. While tomatoes sprout happily, and rapidly, in the laboratory, growing a whole tree from a single, genetically altered cell in a test tube is a tricky process that takes years, not months. Moreover. little is known about tree genes. Some trees, such as pine trees. have a lot of DNA-roughly ten times as much as human. And, whereas the Human Genome Project is more than half-way throughits task of isolating and sequencing the estimated 100,00 genes in human cells. similar efforts to analyzetree genes are still just saplings (幼苗).
Given the large number of tree genes and the little that is known about them, tree engineers are starting with a search for genetic "markers". The first step is to isolate DNA from trees with desirable propertiessuch as insect resistance. The next step is to find stretches of DNA that show the presence of a particular gene. Then, when you mate two trees with different desirable properties, it is simple to check which offspring contain them all by looking for the genetic markers. Henry Amerson, at North Carolina State University, is using genetic markers to breed fungal resistance into southern pines. Billions of these are grown across America for pulp and paper, and outbreaks of disease are expensive. But not all individual trees are susceptible. Dr. Amerson’s group has found markers that distinguish fungus-resistant stock from disease-prone trees.Using traditional breeding techniques, they are introducing the resistance genes into pines on test sites in America.
Using generic markers speeds up old-fashioned breeding methods becauseyou no longer have to wait for the tree to grow up to see if it has the desiredtraits. But it is more a sophisticated form. of selective breeding. Now. however.interest in genetic tinkering (基因修补) is also gaining ground. To this end, Dr.Amerson and his colleagues are taking part in the Pine Gene Discovery Project. an initiative to identify and sequence the 50,000-odd genes in the pine tree&39;s genome. Knowing which gene does what should make it easier to know what to alter.
测试题
Compared with genetic engineering of food crops, genetic engineering of trees____________________.

A.began
I.has
J.is
K.was

5.Women who drank three or more cups of coffee a day were 30 percent less likely to have memory decline at age 65 than whose who drank one cup or less daily. And the benefit increased with age. Women over age 80 who drank three or more cups of coffee a day were about 70 percent less likely to have memory decline than those who drank one cup or less. the researchers said.
Caffeinated tea had the same effect in the women. the study found, although more was needed to get the same caffeine boost. "Count roughly two cups of tea for a cup of coffee," said study leader Karen Ritchie of INSERM, the French National Institute for Health and Medical Research. But the researchers didn&39;t find a similarly protective effect in men, although other studies have found a benefit to males.
How might caffeine help ward off cognitive decline? "It is a cognitive stimulant." said Ritchie. It also helps to reduce levels of the protein called beta amyloid in the brain. she said. "whose accumulation is responsible for Alzheimer&39;s disease but which also occurs in normal aging."
Ritchie said she wasn&39;t sure why men in the study didn&39;t benefit from caffeine. "Our hypothesis is that either women metabolize caffeine differently than men, or there may be an interaction of the caffeine with the sex hormones.the estrogen-progesterone balance," she said.
The French study confirms previous research, said William Scott. professor of medicine at the University of Miami Miller School of Medicine. who has researched caffeine&39;s beneficial effects against Parkinson&39;s disease, also a neurodegenerative disorder.

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Caffeinated
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测试题
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8.The health-care economy is filled with unusual and even unique economic relationships. One of the least understood involves the peculiar roles of producer or "provider" and purchaser or "consumer" in the typical doctor-patient relationship. In most sectors of the economy, it is the seller who attempts to attract a potential buyer with various inducements of price, quality, and utility, and it is the buyer who makes the decision, Such condition, however, does not prevail in most of the health-care industry.
In the health-care industry, the doctor-patient relationship is the mirror image of the ordinary relationship between producer and consumer. Once an individual has chosen to see a physician-and even then there may be no real choice-it is the physician who usually makes all significant purchasing decisions: whether the patient should return "next Wednesday", whether X-rays are needed, whether drugs should be prescribed, etc. It is a rare and sophisticated patient who will challenge such professional decisions or raise in advance questions about price, especially when the disease is regarded as serious.
This is particularly significant in relation to hospital care. The physician must certify the need for hospitalization, determine what procedures will be performed, and announce when the patient may be discharged. The patient may be consulted about some of these decisions, but in the main it is the doctor&39;s judgments that are final. Little wonder then that in the eye of the hospital it is the physician who is the real "consumer." As a consequence, the medical staff represents the "power center" in hospital policy and decision-making, not the administration.

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In
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This
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Although
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测试题
What&39;s
G.To
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B.To
I.
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D.To
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9.You&39;ve decided to try advertising your business with post cards. The idea came to you from the post cards you receive from other businesses. You like the idea because it seems easy to do and economical. However, you&39;ve never tried this before so you question whether this method will bring you customers.
Let me say this first, "All Forms of Advertising Work! " However, you have to clearly understand how the advertising medium works and realize that each form. has its Limitations along with costs associated with it.
Advertising in any medium has always been about repetition and getting your name remembered. It&39;s called "Branding". Study businesses that use television commercials, They are constantly repeating their business message 1000&39;s of times a day. They are the best free examples to watch and learn from.
So for your business, you can conclude that the more your prospects see your name or message repeated. the easier it is for them to get to know you and what you offer. Then it becomes an easier task to get them to buy from you. So how does post card advertising work? You create an ad on a post card. This can be done in your favorite graphics or word program. Then use the mail merge feature in the program to insert mailing addresses automatically. In case you haven&39;t set up your address book you would need co do this before you do a mail merger.
Print out the cards, stamp them and then mail them out. If done correctly and repeated over and over again your customer base will grow. This is the simple mechanics of post card advertising. How much should you send out? I would start small and build from that. This gives you the ability to spend a little at a time while measuring how much each mail out converts. This keeps your advertising costs down and manageable.
Start with ,500 post cards a month. Only target prospects you know that would use your product and/or services. Then I would repeat the mail out to the same group over the next 1-2 years. Even if they do not buy the first or second time after they&39;ve received your card, t.hey are beginning to get to know you and your product and/or services. As time goes by your chances of converting them to a buyer increases.There is also a good chance that those you target may pass your offer onto someone else.
测试题
Branding is a way of advertising that get the customers remember the brand of a product by means of_________.

A.
Let
B.
Advertising
C.
So
D.
Print
E.
Start
F.hey
G.There
H.
测试题
Branding
I.