单选题I had no ______ of who I was or what I was going to be. A. mind B. idea C. think D. thought

单选题Marry has come; I will put______plate on the dining table.

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单选题If you are a fan of science fiction, you've no doubt encountered the term nanotechnology. Yet over the past year also, a series of breakthroughs have transformed nanotech from sci-fi fantasy into a real world. Applied science, in the process, inspired huge investments by business, academia, and government. In industries as diverse as health care, computers, chemicals, and aerospace, nanotech is overhauling production techniques, resulting in new and improved products, some of which may already be in your home or workplace. The inspiration for nanotech goes back to a 1959 speech by the late physicist Richard Feynman, then a professor at the California Institute of Technology, titled "There's Plenty of Room at the Bottom. " Four decades later, Chad Mirkin, a Chemistry professor at Northwestern University's $ 34 million nanotech center, used a nanoscale device to etch most of Feynman's speech onto a surface the size of about 10 tobacco smoke particles. What accounts for the sudden acceleration of nanotechnology? A key breakthrough came in 1990, when researchers at IBM's Almaden Research Center succeeded in rearranging individual atoms at will. Using a device known as a scanning probe microscope, the warn slowly moved 35 atoms to spell the three-letter IBM logo, thus proving Feynman right. The entire Logo was less than three nanometers. Soon, scientists were not only manipulating individual atoms but "spray painting" with them as well. Using a tool known as a molecular beam epitary, scientists have learned to create ultra fine films of specialized crystals, built up one molecular layer at a time. This is the technology used today to build read-head components for computer hard drives. The next stage in the development of nanotechnology borrows a page from noture. Building a supercomputer no bigger than a speck of dust might seem an impossible task, until one realizes that evolution solved such problems more than a billion years ago. Living cells contain all sorts of anisole motors made of proteins that perform myriad mechanical and chemical functions, from muscle contraction to photosynthesis. In some instances, such motors may be re-engineered, or imitated, to produce products and processes useful to humans. How are these biologically inspired machines constructed? Often, they construct themselves, manifesting a phenomenon of nature known as self assembly. The macromolecules of such biological machines have exactly the right shape and chemical binding preferences to ensure that when they combine they will snap together in predesigned ways. For example, the two strands that make up DNA's double helix match each other exactly, which means that if they are separated in a complex chemical mixture, they are still able to find each other easily.

单选题The scientists have come to the conclusion, based on the signals and photographs sent back by the satellite, ______there is no life on Venus.

单选题A. machine B. attention C. major D. China

单选题The country has ______ people and ______ money ______ spent on tobacco every year. A. a large quantity of, a number of, are B. plenty of, a great deal, are C. a great deal of, plenty of, is D. a large number of, a large amount of, is

单选题While still in its early stages, welfare reform has already been judged a great success in many states—at least in getting people off welfare. It"s estimated that more than two million people have left the rolls since 1994. In the past four years, welfare rolls in Athens County have been cut in half. But 70 percent of the people who left in the past two years took jobs that paid less than $ 6 an hour. The result： The Athens County poverty rate still remains at more than 30 percent— twice the national average. For advocates (代言人) for the poor, that"s an indication that much more needs to be done. "More people are getting jobs, but it"s not making their lives any better," says Kathy Lairn, a policy analyst at the Center on Budget and Policy Priorities in Washington. A center analysis of U.S. Census data nationwide found that between 1995 and 1996, a greater percentage of single, female-headed households were earning money on their own, but that average income for these households actually went down. But for many, the fact that poor people are able to support themselves almost as well without government aid as they did with it is in itself a huge victory. "Welfare was a poison. It was a toxin (毒素) that was poisoning the family," says Robert Rector, a welfare-reform policy analyst. "The reform is changing the moral climate in low-income communities. It"s beginning to rebuild the work ethic (工作道德), which is much more important. " Mr. Rector and others argued that once "the habit of dependency is cracked," then the country can make other policy changes aimed at improving living standards. (286 words)

单选题I cannot find my umbrella. I must have ______ it on the bus yesterday.

单选题Although most dreams apparently happen ______, dream activity may be provoked by external influences. A. spontaneously B. simultaneously C. homogeneously D. instantaneously

单选题They provide a means of keeping ______ of the thousands of journal papers that are published monthly or quarterly.

单选题What things in life aye you most desirous ______ attaining? A. to B. for C. with D. of

单选题It has been a wretched few weeks for America's. celebrity bosses. AIG's Maurice Greenberg has been dramatically ousted from the firm through which he dominated global insurance for decades. At Morgan Stanley a mutiny is forcing Philip Purcell, a boss used to getting his own way, into an increasingly desperate campaign to save his skin. At Boeing, Harry Stonecipher was called out of retirement to lead the scandal-hit firm and raise ethical standards, only to commit a lapse of his own, being sacked for sending e-mails to a lover who was also an employee. Carly Fiorina was the most powerful woman in corporate America until a few weeks ago, when Hewlett-Packard (HP) sacked her for poor performance. The fate of Bernie Ebbers is much grimmer. The once high-profile boss of WorldCom could well spend the rest of his life behind bars following his conviction last month on fraud charges. In different ways, each of these examples appears to point to the same welcome conclusion: that the imbalance in corporate power of the late 1990s, when many bosses were allowed to behave like absolute monarchs, has been corrected. Alas, appearances can be deceptive. While each of these recent tales of chief-executive woo is a sis of progress, none provides much evidence that the crisis in American corporate governance is yet over. In fact, each of these cases is an example of failed, not successful, governance. At the very least, the beards of both Morgan Stanley and HP were far too slow to address their bosses' inadequacies. The record of the Boeing beard in picking chiefs prone to ethical lapses is too long to be dismissed as mere bad luck. The fall of Messrs Greenberg and Ebbers, meanwhile, highlights the growing role of government-and in particular, of criminal prosecutors in holding bosses to account: a development that is, at best, a mixed blessing. The Sarbanes-Oxley act, passed in haste following the Enron and WorldCom scandals, is imposing heavy costs on American companies; whether these are exceeded by any benefits is the subject of fierce debate and may not be known for years. Eliot Spitzer, New York's attorney-general, is the leading advocate and practitioner of an energetic "law enforcement" approach. He may be right that the recent burst of punitive actions has been good for the economy, even if some of his own decisions have been open to question. Where he is undoubtedly right is in arguing that corporate America has done a lamentable job of governing itself. As he says in an article in the Wall Street Journal this week: "The hour cede among CEOs didn't work. Board oversight didn't work. Ser-regulation was a complete failure." AIG's board, for example, did nothing about Mr Greenberg's use of murky accounting, or the conflicts posed by his use of offshore vehicles, or his constant bullying of his critics let alone the firm's alleged participation in bid-rigging--until Mr Spitzer threatened a criminal prosecution that might have destroyed the firm.

单选题Why are some of us good at math, or writing, while others ______ at art or basketball?(2002年上海交通大学考博试题)

单选题Some 121 countries may be designated "developing", and of this 121, seventeen countries ______ more than four-fifths of energy consumption.

单选题--Do you like my new shoes? They were only $15. --Wow! That’s cheap, what a ________ !

单选题I wish that he hadn't had such a bad cold because I am sure that he ______ the performance,

单选题It looked just like another aircraft from the outside. The pilot told his young passengers that it was built in 1964. But appearances were deceptive, and the 13 students from Europe and the USA who boarded the aircraft were in for the flight of their lives. Inside, the area that normally had seats had become a long white tunnel. Heavily padded(填塞)from floor to ceiling, it looked a bit strange. There were almost no windows, but lights along the padded walls illuminated it. Most of the seats had been taken out, apart from a few at the back, where the young scientists quickly took their places with a look of fear. For 12 months, science students from across the continents had competed to win a place on the flight at the invitation of the European Space Agency. The challenge had been to suggest imaginative experiments to be conducted in weightless conditions. For the next two hours, the flight resembled that of an enormous bird which had lose its reason, shooting upwards towards the heavens before rushing towards Earth. The invention was to achieve weightlessness for a few seconds. The aircraft took off smoothly enough. But any feelings that I and the young scientists had that we were on anything like a scheduled passenger service were quickly dismissed when the pilot put the plane into a 45-degree climb which lasted around 20 seconds. Then the engines cut out and we became weightless. Everything became confused and left or right, up or down no longer had any meaning. After ten seconds of free-fall descent(下降)the pilot pulled the aircraft out of its nosedive. The return of gravity was less immediate than its loss, but was still sudden enough to ensure that some students came down with a bump. Each time the pilot cut the engines and we became weightless, a new team conducted its experiment. First it was the Dutch who wanted to discover how it is that cats always land on their feet. Then the German team who conducted a successful experiment on a traditional building method to see if could be used for building a further space station. The Americans had an idea to create solar sails that could be used by satellites. After two hours of going up and down in the lane doing their experiments, the predominate feeling was one of excitement rather than sickness. Most of the students thought it was an unforgettable experience and one they would be keen to repeat.