单选题Lots of creatures already reproduce without sex. Since the birth of Louise Brown, the first test-tube baby, in 1978, (1) of human beings (2) in laboratory glassware rather than in bed. If human cloning becomes possible—and since the birth of a sheep called Dolly, (3) doubt that it will be feasible to clone a person by 2025—even the link between sex organs and reproduction (4) . You will then be able to take a cutting from your body and grow a new person, (5) you were a willow tree. (6) , we have already divorced sex from reproduction. In the 1960s, the contraceptive pill freed women to enjoy sex for its own sake. (7) , greater tolerance of homosexuality signaled society's acceptance of nonreproductive sex of another sort. These changes are only continuations of a (8) that started perhaps a million years ago. Human beings (9) the interest in infertile, social sex with a few other species: dolphins, apes and some birds. But (10) sex is too good for human beings to (11) , more and more people will abandon it as a (12) of reproduction. In the modern world, you can (13) have sex and parenthood without suffering the bit (14) . Some Hollywood actresses (15) the urge for mothering by electing to adopt children (16) spoil their figures (as they see it) by childbearing. For people as beautiful as this, the temptation to (17) a clone (reared in a surrogate womb) could one day be (18) . However, human cloning and designer babies are probably not (19) . Even assuming that the procedures are judged safe and efficient in farm animals, still a long way off, they will be heavily (20) , if not banned, by many governments for human beings.

单选题The population of the United States is only 6% the world's population, but Americans (1) one third of all the energy (2) in the world. This fact alone says that Americans need to use less energy. And because the price of energy had been rising very rapidly (3) the limited supplies of oil in particular, Americans are becoming aware to the need to (4) energy. In California we have a California Energy Commission which has set up in the past five years to (5) plan for our future energy rise. We have (6) laws in California to help us conserve energy. First of all, our houses in California have been very (7) of energy in the past. They were not (8) very carefully and so the heat would go out of the house very rapidly. Now we require that the homes have a (9) level of insulation, and so the homes built now are much more (10) (11) , in transportation (12) a large percentage of oil energy is used, we need to develop more public transportation. In China, of course, you have a very good public-transportation system. And it is a (n) (13) for the kind of thing we need to develop more in the United States. Automobiles are also becoming more (14) The smaller automobile with efficient engine can help to conserve a large amount of energy along with planning our (15) more carefully. Many different studies have shown that we could (16) our energy consumption by (17) half or two thirds and still have the (18) quality of life. And many different types of technologies are currently being researched as to (19) they can be built to use 20 energy and still supply the same service.

单选题How many people are there in the United States in 1987?

单选题As for globalization, Michael Tenet's attitude to it is most probably one of

单选题{{B}}Text 1{{/B}} I don't know why UFOs are never sighted over large cities by hordes of people. But it is consistent with the idea that there are no space vehicles from elsewhere in our skies. I suppose it is also consistent with the ideas that space vehicles from elsewhere avoid large cities. However, the primary argument against recent extraterrestrial visitation is the absence of evidence. Take leprechauns. Suppose there are frequent reports of leprechauns. Because I myself am emotionally predisposed in favor of leprechauns, I would want to check the evidence especially carefully. Suppose I find that 500 picnickers independently saw a green blur in the forest. Terrific. But so what? This is evidence only for a green blur. Maybe it was a fast hummingbird. Such cases are reliable but not particularly interesting. Now suppose that someone reports: "I was walking through the forest and came upon a convention of 7000 leprechauns. We talked for a while and I was taken down into their hole in the ground and shown pots of gold and feathered green hats. "I will reply: "Fabulous! Who else went along?" And he will say, "Nobody," or "My fishing partner. "This is a case that is interesting but unreliable. In a case of such importance, the uncorroborated testimony of one or two people is almost worthless. What I want is for the 500 picnickers to come upon the 7000 leprechauns.., or vice versa. The situation is the same with UFOs. The reliable cases are uninteresting and the interesting cases are unreliable. Unfortunately, there are no cases that are both reliable and interesting.

单选题It can be safely concluded from the text that

单选题The best title for Sis passage may be

单选题The author mentions the work of Harold Edgerton in order to provide an example of

单选题Cameron Walker learned the hard way that sharing information online can have unintended consequences. In 2005, the sophomore at Fisher College in Boston organized a student petition dedicated to getting a campus police guard fired and posted it on the popular college social network Facebook. com. Walker wrote that the guard "loves to antagonize students.., and needs to be eliminated. " It was a poor choice of words. Another student informed school officials, who logged on and interpreted the comments as threatening. Though Walker claimed he was trying only to expose the guard's demeanor, he was expelled. He's now enrolled at another college and admits he made a serious mistake. "I was a naive 21-year-old," he says. Creating a page on a social-networking site is now a cherished form of self-expression at universities around the world. Students use ad-supported services like Facebook, MySpace, TagWorld and Bebo to make friends, plan their Social lives and project their personalities. The most popular site among college students is Facebook, with more than 8 million members. A student's personal Facebook page is usually a revealing, dynamic chronicle of campus life—one clearly not meant for the eyes of parents, teachers or anyone else older than 25. But adults are taking notice. Sites like Facebook are accessible to nearly anyone willing to spend the time to gain access: teachers, school administrators, even potential employers and the police. Such online services can create the illusion of privacy where none actually exists. Facebook, in particular, was designed to emphasize privacy and intimacy. Only other users at your school (with the same college e-mail domain name), and those in networks you join, can see your home page. But determined off-campus visitors can persuade a student or alumnus to help them access the student's page. What happens when the identity you reveal to friends suddenly overwhelms the facade you present to grown-ups? The results can be awkward—or worse. Photos from drunken parties, recollections of sexual escapades, or threats—all these indiscretions, posted online, have gotten students suspended or expelled, or harmed job prospects. In a couple of decades, a presidential candidate may be called on to answer for a college misadventure that he or she impulsively detailed in a blog entry. Not all students want to temper their behavior. They point out that the Internet lets them express themselves and find like-minded souls. Still, adults aren't likely to stop prying any time soon. That means students who use Facebook and MySpace have a new burden. The Web may seem ephemeral, but what you casually post one night might just last a digital eternity. While social networking represents a powerful tool for today's students, they're advised to be prudent. Even if they have no plans to run for president someday.

单选题The phrase "make a go of it" (Paragraph 1) most probably means

单选题It is the staff of dreams and nightmares. Where Tony Blair's attempts to make Britain love the euro have fallen on deaf ears, its incarnation as notes and coins will succeed. These will be used not just in the euro area but in Britain. As the British become accustomed to the euro as a cash currency, they will warm to it—paving the way for a yes note in a referendum. The idea of euro creep appeals to both sides of the euro argument. According to the pros, as Britons become familiar with the euro, membership will start to look inevitable, so those in favor are bound to win. According to the antis, as Britons become familiar with the euro, membership will start to look inevitable, so those opposed must mobilize for the fight. Dream or nightmare, euro creep envisages the single currency worming its way first into the British economy and then into the affections of voters. British tourists will come back from their European holidays laden with euros, which they will spend not just at airports but in high street shops. So, too, will foreign visitors. As the euro becomes a parallel currency, those who make up the current two-to-one majority will change their minds. From there, it will be a short step to decide to dispense with the pound. Neil Kinnock, a European commissioner and former leader of the Labor Party, predicts that the euro will soon become Britain's second currency. Hans Eichel, the German finance minister, also says that it will become a parallel currency in countries like Switzerland and Britain. Peter Hain, the European minister who is acting as a cheerleader for membership, says the euro will become "a practical day-to-day reality and that will enable people to make a sensible decision about it.' As many as a third of Britain's biggest retailers, such as Marks and Spencer, have said they will take euros in some of their shops. BP has also announced that it will accept euros at some of its garages. But there is less to this than meet the eye. British tourists can now withdraw money from cashpoint from European holiday destinations, so they are less likely than in the past to end up with excess foreign money. Even if they do, they generally get rid of it at the end of their holidays, says David Southwell, a spokesman for the British Retail Consortium (BRC).

单选题So what is depression? Depression is often more about anger turned (1) than it is about sadness. But it's usually (2) as sadness. Depression can (3) at all ages, from childhood to old age, and it's the United States' No. 1 (4) problem. When someone is depressed, her behavior (5) change and she loses interest in activities she (6) enjoyed (like sports, music, friendships). The sadness usually lasts every day for most of the day and for two weeks or more. What (7) depression? A (8) event can certainly bring (9) depression, but some will say it happens (10) a specific cause. So how do you know if you're just having a bad day (11) are really depressed? Depression affects your (12) , moods, behavior and even your physical health. These changes often go (13) or are labeled (14) simply a bad case of the blues. Someone who's truly (15) depression will have (16) periods of crying spells, feelings of (17) (like not being able to change your situation) and (18) (like you'll feel this way forever), irritation or agitation. A depressed person often (19) from others. Depression seldom goes away by itself, and the greatest (20) of depression is suicide. The risk of suicide increases if the depression isn't treated.