单选题 Though it was late in the night, ______ he continued to work vigorously.

单选题 We can begin our discussion of 'population as a global issue' with what most persons mean when they discuss 'the population problem': too many people on earth and a too rapid increase in the number added each year. The facts are not in dispute. It was quite right to employ the analogy that likened demographic (人口统计学的) growth to 'a long, thin power fuse that bums steadily and haltingly until it finally reaches the charge, and explodes'. To understand the current situation, which is characterized by rapid increases in population, it is necessary to understand the history of population trends. Rapid growth is a comparatively recent phenomenon. Looking back at the 8, 000 years of demographic history, we find that populations have been virtually stable or growing very slightly for most of human history. For most of our ancestors, life was hard, often nasty, and very short. There was high fertility in most places, but this was usually balanced by high mortality. For most of human history, it was seldom the case that one in ten persons would live past forty, where infancy and childhood were especially risky periods. Often, societies were in clear danger of extinction because death rates could exceed their birth rates. Thus, the population problem throughout most of history was how to prevent extinction of the human race. This pattern is important to know. Not only does it put the current problems of demographic growth into a historical perspective, but it suggests that the cause of rapid increase in population in recent years is not a sudden enthusiasm for more children, but an improvement in the conditions that traditionally have caused high mortality. Demographic history can be divided into two major periods: a time of long, slow growth which extended from about 8000 B. C. till approximately 1650 A. D. and a period of rapid, dramatic growth since 1650. In the first period of some 9, 600 years, the population increased from some 8 million to 500 million in 1650. Between 1650 and the present, the population has increased from 500 million to more than 4 billion. And it is estimated that by the year 2020 there will be 8 billion people throughout the world. One way to appreciate this dramatic difference in such abstract numbers is to reduce the time frame to something that is more manageable. Between 8000 B. C. and 1650, an average of only 50, 000 persons was being added annually to the world's population each year. At present, this number is added every six hours. The increase is about 80, 000, 000 persons annually.

单选题"But the doctor can't use just anyone's blood. The donor's blood has to be of a type that won't be destroyed by your blood." This statement means that______.

单选题The Saturday Evening Post became symbolic of the reading fare of middle-class America. In 1897 Curtis began to revive （重振） the Post on the proposition that a mans chief interest in life is the fi

单选题We find it extremely difficult to ______ the meaning of what he has just said. A. get into B. get over C. get across D. get at

单选题It is no use ________ to George as he is a very stubborn person.

单选题Will it rain tomorrow? I hope ______. A. no B. yes C. not D. will

单选题From the time of the Greeks to the Great War, medicine's job was simple: to struggle with ______ diseases and gross disabilities, to ensure live births, and to manage pain.

单选题You have nothing to ______ by refusing to listen to our advice,

单选题The basis of this consensus is a belief that improved relations with the U. S. would serve Iranian interests on a variety of fronts, including Iraq, Afghanistan, oil production, foreign investment and Iran's nuclear energy program.

单选题Can machines perform the same tasks _______ ?

单选题Do you know any other foreign languages ______French?

单选题Hawaii's native minority is demanding a greater degree of sovereignty over its own affairs. But much of the archipelago's political establishment, which includes the White Americans who dominated until the Second World War and people of Japanese, Chinese and Filipino origin, is opposed to the idea. The islands were annexed by the US in 1898 and since then Hawaii's native peoples have fared worse than any of its other ethnic groups. They make up over 60 percent of the state's homeless, suffer higher levels of unemployment and their life span is five years less than the average Hawaiians. They are the only major US native group without some degree of autonomy. But a sovereignty advisory committee set up by Hawaii's first native governor, John Waihee, has given the natives' cause a major boost by recommending that the Hawaiian natives decide by themselves whether to re-establish a sovereign Hawaiian nation. However, the Hawaiian natives are not united in their demands. Some just want greater autonomy with the state—as enjoyed by many American Indian natives over matters such as education. This is a position supported by the Office of Hawaiian Affairs (OHA), a state agency set up in 1978 to represent to natives' interests and which has now become the moderate face of the native sovereignty movement. More ambitious in the Ka Lahui group, which declared itself a new nation in 1987 and wants full, official independence from the US. But if Hawaiian natives are given greater autonomy, it is far from clear how many people this will apply to. The state authorities only count those people with more than 50 percent Hawaiian blood as native. Native demands are not just based on political grievances, though. They also want their claim on 660,000 hectares of Hawaiian crown land to be accepted. It is on this issue that native groups are facing most opposition from the state authorities. In 1933, the state government paid the OHA US $136 million in back rent on the crown land and many officials say that by accepting this payment the agency has given up its claims to legally own the land. The OHA has vigorously disputed this.

单选题It seems that the President, in face of the present situation,

单选题The old worker has been on the ______ in this factory for nearly 20 years. A. pay packet B. payoff C. payroll D. payment

单选题 A network chatting is a limp substitute for meeting friends over coffee.

单选题Our planet is like d big spaceship. Our atmosphere acts 【1】 a shield against harmful radiation and space debris. 【2】 holds the air and people on the spaceship, 【3】 everything doesn''t float away. Each of us is an astronaut and our spaceship, the earth, provides our food and water. The sun is our energy 【4】 and without it we would not be able to survive. 【5】 every spaceship, the earth is a closed system. The only thing we receive from the outside is energy from: the sun. Everything else must be used 【6】 again. We astronauts don''t seem to realize that this spaceship is the 【7】 one we''ve got We 【8】 its resources and waste the energy that the plants have stored from the sun. If we 【9】 our spaceship, we will destroy ourselves as well Maybe if we look at the universe which surrounds us, we will appreciate our own spaceship more and take 【10】 care of it.

单选题He ______ that he has discovered a new planet.

单选题What we don"t know about kids and television could fill a weeklong miniseries. Given worries about everything from childhood obesity to scholastic shortcomings, it"s high time to find out. But before Congress approves $20 million a year to research children and the media, it should get more specific assurances that the money will pay for comprehensive, high-quality studies instead of bits of teasing information. Up to now, a patchwork of research on kids and TV has yielded plenty of suspicion but little real knowledge. Yes, a study two years ago found that teenagers who watched a lot of TV tended to be more aggressive. But what does that mean? Maybe more-aggressive kids are drawn more to TV. Ditto for the April study about preschoolers who watch hours of TV tending to have attention-span problems later on. It"s possible that children with a propensity toward attention problems are drawn more to that jumpy on-screen world in the first place. For better or worse, U.S. kids spend a lot of time in front of a TV or computer screen, two hours daily for those 5 and younger. If the schools spent two hours a day on a single activity, there would be intense concern about its value. So there is worth in legislation by Sen. Joe Lieberman to provide $100 million over five years for research on child development and electronic media. A scientific panel would set up a list of the key issues to be studied and review grant applications from universities or nonprofit institutes. This centralized approach makes sense—especially considering the money involved. Good studies are costly, and there haven"t been enough of them on this subject. Merely showing a link between TV viewing and a certain behavior doesn"t prove anything. In addition to the possibility the behavior is causing the TV watching instead of the other way around, a third factor could be causing both. Only carefully controlled studies obtain worthwhile results. At their best, such studies might tell us whether educational computer games for toddlers interrupt the natural development of the brain instead of aiding it, or whether seeing Ronald McDonald cavort on a soccer field makes a child more active or just more likely to crave French fries. Parents could decide limits based on more than instinct. But before spending the money, Congress should insist on a quality of research that will give the public answers about TV instead of more arguments. This shouldn"t be a handout to think tanks for more mushy research on a complicated but vital issue.