单选题Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery of genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years. While it"s true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so-called stem cells haven"t begun to specialize. Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells—brain cells in Alzheimer"s, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few; if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue. It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural, gut, muscle and bone cells. The process still can"t be controlled, and may have unforeseen limitations; but if efforts to understand and master stem cell development prove successful, doctors will have a therapeutic tool of incredible power. The same applies to cloning, which is really just the other side of the coin; true cloning, as first shown with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resetting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full fledged animal, genetically identical to its parent. For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year. Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells: the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure."

单选题He read through the papers and made a(n)______of their contents.

单选题The scientist's discovery will have a profound influence on mankind.

单选题You must insist that students give a truthful answer______with the reality of their world.

单选题The market for processor chips is now a two-horse race, and Intel and AMD will probably alternate in technical leadership, suggests Nathan Brookwood of Insight 64 a research firm.

单选题Everyone knows that the firefly is a(n) ______ insect.

单选题By the time you come back I ______ the work. A. finish B. shall finish C. shall have finished D. would have finished

单选题If you don't have as much sleep as your body needs, you will ______.

单选题English ______ in meaningful situations. A) must learn B) is to learn C) has learnt D) must be learned

单选题The Asian tiger mom that Amy Chua portrays in her new book may seem like just one more species in the genus Extreme Parent — the counterpart to the hovering American Parents helicopters or the Scandinavian Curling Parents, who frantically rush ahead of their children, sweeping their paths clear of the tiniest obstacles. The common characteristics include an obsession with a child's success, a reflex to treat kids as extensions or reflections of oneself and patterns of conduct that impartial observers might class as insane if not criminal, if not both. In Chua's case, this famously includes prohibiting grades lower than an A, TV, playdates and sleepovers, and warning her pianist child that "if the next time's not PERFECT, I'm going to TAKE ALL YOUR STUFFED ANIMALS AND BURN THEM." In the case of the classic Western helicopter parent, it starts with Baby Einstein and reward charts for toilet training, and it never really ends, which is why colleges have to devote so many resources to teaching parents how to leave their kids alone. But it is the differences between the Tigers and the Choppers that help explain the furor Chua has caused, at least in the U. S. Tigers fixate on success, defined as achievement in precision-oriented fields like music and math; Choppers are obsessed with failure and preventing it at all costs. Tigers operate in a culture of discipline; Choppers, in a culture of fear. Tigers view children as tough, able to take the abuse; Choppers view them as precious, to be raised under glass. Their fury at a bad grade is more likely to land on the teacher than on the child. And if Chua appears to sentence her children to slave labor, Western parents enshrine their children and crave their friendship. "The thing that impresses me most about America," observed Edward, Duke of Windsor, who knew something about indulgence, "is the way parents obey their children." There is something bracing about Chua's apparent indifference to her daughters' hostility, especially for parents who have learned that even if you let your teenagers spend 50 hours a week on Facebook, they'll still find reasons to hate you. The reactions to Chua's book, Battle Hymn of the Tiger Mother, have ranged from praise for her honesty to scorn for her "extreme, rigid and authoritarian approach," as one critic put it. But in less hysterical precincts, she elicits a more conflicted response. First reaction: My God, she's crazy. Second reaction: Maybe she's right. I suspect one reason the book has touched such a nerve is a suspicion among the Choppers that an excessive fear of failure guarantees it — that if you don't let your kids get clobbered now and then by a tough teacher, they'll never have the resilience to thrive as adults in a competitive economy. Twenty-first century parenting already seemed like a gladiatorial contest, its battles fought in playgrounds , at book clubs and especially online, with the rise of parenting websites where parents — O. K. , mainly moms — claw and bite. You let your toddler have Froot Loops? You quit karate lessons? Western parents may exalt freedom and self-expression, but in many ZIP codes, parenting is a highly conformist activity, with protocols every bit as strict as Chua's. Commenters spank the moms who appear insufficiently committed to breast feeding. Some of Chua's critics sound just as smug when they declare that the Tigers' " inside-the-box thinking is why Bill Gates, Steve Jobs, Michael Dell and/or a cure for cancer will never come from China. " Too much discipline, they argue, makes for submissiveness and lack of imagination, because imagination by its nature is subversive; it colors outside the lines. Likewise, invention, the creation of something utterly new, violates the authority of the present and the tyranny of tradition.But this much derision, I suspect, reflects some doubts. Western families have no monopoly on happiness, and those of the helicopter variety at least do not exactly encourage wild individuality in their children. Trust your instincts, Dr. Spock advised back in 1946; but that involves a leap of faith that many modern parents find terrifying. Helicopter parents are great believers in expertise: read enough books, consult enough professionals, and you can crack the parenting code. Chua's daughters are, by all accounts, girls any parent would be proud of. But maybe the real appeal is her tone of certainty in discussing something so confounding as child rearing — as if it's a puzzle to be solved rather than a picture to be painted, and there's no way to know what it will look like until it's done.

单选题Which of the following statements may not be the reason for Shakespeare's success?

单选题 Federal Reserve Board Chairman Alan Greenspan laid forth the intellectual basis for the likely continued aggressive easing in monetary policy in the weeks ahead in his semi-annual monetary policy report to Congress. The broader point in his prepared testimony is that the improved information and production controls evident in the new economyinduce companies to respond more quickly and in tandem to changes in their business. Mistakes are still made as is evidenced by the unwanted buildup of inventories at the end of last year, but any mistakes are more aggressively addressed than in the past, as is evidenced by manufacturers' recent slashing of production. Moreover, the increasingly dramatic shifts in economic activity are particularly hard on confidence. Consumers and businesses literally freeze up due to the heightened uncertainty, and run from any perceived risks and curtail their spending and investment. If confidence deflates by enough, then a recession will ensue. Confidence has also been under extraordinary pressure in recent months due to surging energy prices and weaker stock prices. Higher energy bills have acted much like a tax increase, save the checks are largely being written to foreign energy producers. The lower stock prices are having a magnified impact due to the dramatic increase in stock wealth since the mid-1990s. The conduct of monetary policy must adjust to all of this, and thus respond more quickly and aggressively than in the past in an effort to shore up confidence. This explains the dramatic and unprecedented action (at least by a Greenspan-led Federal Reserve) to cut the federal funds rate target by 100 basis points in January: This also suggests that substantially more easing is on the way in the weeks ahead. Just when and by how much will depend on whether confidence continues to fall. The chairman made a point to note that policymakers have significant latitude to ease policy aggressively since inflation remains low and tame. Despite surging energy prices, inflation and inflation expectations remain contained. The Federal Reserve's economic projections for this year provided as part of the testimony support this non-recessionary view. Real GDP is expected to grow by between 2% and 2. 5% between the fourth quarter of 2000 and the fourth quarter of this year. Since this is below the economy's potential growth, the jobless rate will rise to approximately 4. 5% by year's end. Inflation will moderate somewhat in response. Recession risks are rising and as high as they have been since the last downturn almost a decade ago. The key buffer between a soft economy and a recessionary one is confidence, and today's testimony by the Federal Reserve chairman clearly indicates that policymakers will be as aggressive as they need to be to ensure that confidence erodes no further. With just a bit of luck they will succeed.

单选题______founded a new school of poetry by the name of metaphysical school.

单选题______ is a fact that English is being accepted as an international language． A．There B．This C．That D．It

单选题Economic activity has been organized on the ______ of cheap and abundant oil from the beginning of the 20th century.

单选题______the meeting himself gave his supporters a great deal of encouragement.

单选题What may chiefly be responsible for the lessons the UK government learnt from the BSE crisis?

单选题Although ______ named until 1812, the metal was used as early as 5100 B.C..