题目内容
（请给出正确答案）
The average number of hours of sleep that an adult needs is ______.
A. approximately six hours
B. around ten hours
C. about eight hours
D. not stated here
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A.A.on average
B.B. at last
C.C.in common
D.D. at present
According to Dr. Liu's paper, the dwindling of biodiversity is due to
A．the reduction in average home size.
B．the improvement of living conditions.
C．the increasing number of residences.
D．the decline of population growth rate.
A、total cost divided by the number of units produced
B、fixed cost divided by the number of units produced
C、extra fixed cost of producing an additional unit of output
D、extra average cost of producing an additional unit of output
E、extra cost of producing an additional unit of output
Which of the following can be inferred from the passage？
A．During its whole history it sold 7,000 prints.
B．The firm's prints were especially popular in Europe.
C．The average number of prints from each picture was fewer than 7,000.
D．Street vendors were among the firm's most effective sale force.
A.$4,800.
B.$16,000.
C.$20,000.
D.$20,800.
These proportions vary somewhat from one area of the nation to another. In all areas, however, families are the fastest-growing sector of the homeless population, and in the Northeast they are by far the largest sector already. In Massachusetts, three-fourths of the homeless now are families with children; in certain parts of Massachusetts—Attleboro and Northampton, for example—the proportion reaches 90 percent. Two thirds of the homeless children studied recently in Boston were less than five years old.
Of the estimated two to three million homeless people nationwide, about 500,000 are dependent children, according to Robert Hayes, counsel to the National Coalition for the homeless. Including their parents, at least 750,000 homeless people in America are family members.
What is to be made, then, of the supposition that the homeless are primarily the former residents of mental hospitals, persons who were carelessly released during the 1970s？ Many of them are, to be sure. Among the older men and women in the streets and shelters, as many as one-third (some believe as many as one-half) may be chronically disturbed, and a number of these people left mental hospitals during the 1970s. But in a city like New York, where nearly half the homeless are small children with an average of six, to operate on the basis of such a supposition makes no sense. Their parents, with an average age of twenty-seven, are not likely to have been hospitalized in the 1970s, either.
According to the statistics, among the homeless in New York there were ______.
A．more people in a families than single persons
B．about six thousand families
C．3 children in a family
D．more families with two parents than one
A.Throughput is the maximum available transmission rate in case of no packet losses.
B.Frame loss rate is the percentage of successfully forwarded packets out of a certain traffic loaD.Causes for packet loss include network congestion, timeout, disorder and frame. error.
C.Latency is the interval from when a packet is received to when it is forwarded in case of no packet losses. Perform. latency test for several times and take their average value.
D.Back-to-back frames refer to maximum number of packets that can be processed by an IP network device, in case of no losses of packets which are received at a minimum transmission interval.
Except for the recession years of 1949, 1954, and 1958, the rate of economic growth exceeded the rate of productivity increase. However, in the late 1950s productivity and labor force were increasing more rapidly than usual, while the growth of output was slower than usual. This accounted for the change in employment rates.
But if part of the national purpose is to reduce and contain unemployment, arithmetic is not enough. We must know which of the basic factors we can control and which we wish to control. Unemployment would have risen more slowly or fallen more rapidly if productivity had in creased more slowly, or the labor force had increased more slowly, or the hours of work had fallen more steeply, or total output had grown more rapidly. These are not independent factors, however, and a change in any of them might have caused change in the other.
A society can choose to reduce the growth of productivity, and it can probably find ways to frustrate its own creativity. However, while a reduction in the growth of productivity at the expense of potential output might result in higher employment in the short run, the long-run effect on the national interest would be disastrous.
We must also give consideration to the fact that hidden beneath national averages is continuous movement into, out of, between, and within labor markets. For example, 15 years ago, the average number of persons in the labor force was 74 million, with about 70 million employed and 3.9 million unemployed. Yet 14 million experienced some term or unemployment in that year. Some were new entrants to the labor fore; others were laid off temporarily, the remainder were those who were permanently or indefinitely severed from their jobs. Thus, the average number unemployed during a year understates the actual volume of involunatary displacement that occurs.
High unemployment is not an inevitable result of the pace of technological change but the consequence of passive public policy. We can anticipate a moderate increase in the labor force accompained by a slow and irregular decline in hours or work. It follows that the output of the economy--and the aggregate demand to buy it--must grow by more than 4 percent a year just to prevent the unemployment rate from rising, and by even more if the unemployment rate is to fall further. Yet our
A．productivity rises at the same rate as growth of the labor force
B．productivity and labor force increase at a greater rate than output
C．output exceeds productivity
D．rate of economic growth is less than the number of man-hours required
Part A
Directions: Read the following four texts. Answer the questions below each text by choosing A, B, C or D. (40 points)
The planet's wild creatures face a new threat from yuppies, empty nesters, singletons and one parent families. Biologists studying the pressure on the planet's dwindling biodiversity today report on a new reason for alarm. Although the rate of growth in the human population is decreasing, the number of individual households is exploding. Even where populations have actually dwindled—in some regions of New Zealand, for instance—the number of individual households has increased, because of divorce, career choice, smaller families and longer lifespans.
Jianguo Liu of Michigan State University and colleagues from Stanford University in California re port in Nature, in a paper published online in advance, that a greater number of individual house holds, each containing on average fewer people, meant more pressure on natural resources. Towns and cities began to sprawl as new homes were built. Each household needed fuel to heat and light it; each household required its own plumbing, cooking and refrigeration. "In larger households, the efficiency of resource consumption will be a lot higher, because more people share things," Dr. Liu said. He and his colleagues looked at the population patterns of life in 141 countries, including 76 "hotspot" regions unusually rich in a variety of endemic wildlife. These hot spots included Australia, New Zealand, the US, Brazil, China, India, Kenya, and Italy. They found that between 1985 and 2000 in the "hotspot" parts of the globe, the annual 3.1% growth rate in the number of households was far higher than the population growth rate of 1.8 %.
"Had the average household size remained at the 1985 level," the scientists report, "there would have been 155m fewer households in hotspot countries in 2000. Paradoxically, smaller households do not mean smaller homes. In Indian River County, Florida, the average area of a one-storey, single family house increased 33 % in the past three decades."
Dr. Liu's work grew from the alarming discovery that the giant pandas living in China's Wolong reserve were more at risk now than they were when the reserve was first established. The local population had grown, but the total number of homes had increased more swiftly, to make greater inroads into the bamboo forests.
Gretchen Daily of Stanford, one of the authors, said: "We all depend on open space and wild places, not just for peace of mind but for vital services such as crop pollination, water purification and climate stabilization. The alarming thing about this study is the finding that, if family groups continue to become smaller and smaller, we might continue losing biodiversity—even if we get the aggregate human population size stabilised."
The first paragraph mainly tells us that
A．the amount of wildlife is diminishing.
B．the population of human is decreasing.
C．New Zealanders live an unstable life.
D．the structure of families is changing.
