Newspapers often tell us of floods in some parts of the United States. Nearly every year on the great central drainages heavy rains and melting snow cause the waters to pour out the mountains and plains, to turn brooks into torrents, and to swell quiet streams into wild uncontrolled rivers. From Cairo to New Orleans, and from Pittsburgh to Paducah, the cry 'River rising!' is a familiar yet fearful voice. . . When the rivers sometimes become too high or too swift to be controlled communities are flooded, families flee from their homes, croplands are washed out, and transportation comes to a halt. Hunger, disease, and death follow the wild waters. Although given less publicity, the agricultural damage done by the many smaller, more frequent floods usually far exceeds the losses caused by the very grand ones. In the Central States, ditches and drains cause the flows from spring rains and melting snow to run far more rapidly than in the days before white men settled on the land. Once, excess spring flood waters emptied into lakes and swampy lands, there to be detained for slow release into stream and rivers. Now, systematic drainage has actually eliminated these natural reservoirs. In the more rolling sections of the East, spring runoff was formerly absorbed and held temporarily in the porous soils beneath the unbroken expanse of forest. When large areas were converted to farm use, removal of the forest and the practice of up-and-down hill plowing deprived the soils of much of their ability to catch and store water. The effects of eliminating the natural forest cover are shown in the gullied farm lands and widened stream channels found in some densely settled areas. Partly because the stream channels are more or less filled with material washed down from the uplands, and partly because storm runoff has increased, the channels are today no longer able to carry all the flow from heavy rains. This explains why the streams overtop banks far more often than in the days before settlement. The best title for the selection would be______.

单项选择题All of the following cause floods EXCEPT______.

单项选择题In order to compensate for the loss of fertile topsoil, farmers have been_______.

单项选择题All of the following are statements about the disadvantages of fertilizers EXCEPT that________.

单项选择题The floods which are given most publicity______.

单项选择题According to the selection, streams overtop their banks partly because______.

单项选择题By 'infrastructure'(Para. 2) the author means_______.

单项选择题The future population will be older than today, and this in turn will change the patterns of social demands. However, Mexico will still be far from the 'aging societies' that will most likely prevail (占优势 ) in the industrialized countries. In less than 25 years, the country will have to add almost as much infrastructure as it has already built up to now, simply to maintain services and production at the current levels. This will be a tremendous challenge, although a similar one was faced successfully in the recent past, when available infrastructure was doubled in two decades or so. It is no wonder that much has been said about the need to reduce or preferably halt Mexico's population control which is taken for granted as both good and necessary. It has also gained supporters in the developing world, and Mexico is no exception. But the arguments about population are complicated, as the following discussion illustrates. Even if Mexico's population reaches 125 million by the year 2010, its population density is still smaller than the 1985 population density of some 50 countries. By international standards Mexico will still not be overpopulated by the year 2010. If wealth is generated by people, the more individuals there are, the greater the wealth that potentially could be generated. Why should Mexico control its population at density levels below those of the richer countries if more population represents the possibility of generating more wealth? On the other hand, it is often pointed out that once sustainability(支撑力) limits are near or are reached, there are decreasing productivity gains (or,perhaps more accurately, increasing productive losses) , and people become a cost rather than an asset. If we assume that there are sustainability limits and that we are close to reaching these limits at a world level, then it is appropriate to check population growth. According to the passage, the population argument is focused on_______.

单项选择题What does the question 'How could you have nine wives?' imply?

单项选择题Questions 6 to 10 are based on the following passage.? The most important thing in the news last week was the rising discussion in Nashville about the educational needs of children. The shorthand(简写)educators use for this is 'pre-K'—meaning instruction before kindergarten—and the big idea is to prepare 4-year-olds and even younger kids to be ready to succeed on their K-12 journey.? But it gets complicated. The concept has multiple forms, and scholars and policymakers argue about the shape, scope and cost of the ideal program.? The federal Head Start program, launched 50 years ago, has served more than 30 million children. It was based on concepts developed at Vanderbilt University's Peabody College by Susan Gray, the legendary pioneer in early childhood education research.? A new Peabody study of the Tennessee Voluntary Pre-K program reports that pre-K works, but the gains are not sustained through the third grade. It seems to me this highlights quality issues in elementary schools more than pre-K, and indicates longer-term success must connect pre-K with all the other issues, related to educating a child.? Pre-K is controversial. Some critics say it is a luxury and shouldn't be free to families able to pay. Pre-K advocates insist it is proven and will succeed if integrated with the rest of the child's schooling. I lean toward the latter view.? This is, in any case, the right conversation to be having now as Mayor Megan Barry takes office. She was the first candidate to speak out for strong pre-K programming. The important thing is for all of us to keep in mind the real goal and the longer, bigger picture.? The weight of the evidence is on the side of pre-K that early intervention (干预)works. What government has not yet found is the political will to put that understanding into full practice with a sequence of smart schooling that provides the early foundation.? For this purpose, our schools need both the talent and the organization to educate each child who arrives at the schoolhouse door. Some show up ready, but many do not at this critical time when young brains are developing rapidly. What does the author say about pre-kindergarten education?

单项选择题A.It made news all over the world。B.It was built for the Royal family。C.It marked a new era in motor travel。D.It attracted large numbers of motorists。