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先天性心脏病最经济、最重要的无创性诊断方法是
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决策支持系统的设计方法目前主要有两种，即信息分析法和 【12】 ，前者用于数据设计，后者用于模型设计。
Text 3 The word conservation has a thrifty meaning. To conserve is to save and protect, to leave what we ourselves enjoy in such good condition that others may also share the enjoyment. Our forefathers had no idea that human population would increase faster than the supplies of raw materials; most of them, even until very recently, had the foolish idea that the treasures were "limitless" and "inexhaustible". Most of the citizens of earlier generations knew little or nothing about the complicated and delicate system that runs all through nature, and which means that, as in a living body, an unhealthy condition of one part will sooner or later be harmful to all the others. Fifty years ago nature study was not part of the school work; scientific forestry was anew idea; timber was still cheap because it could be brought in any quantity from distant woodlands; soil destruction and river floods were not national problems; nobody had yet studied long-term climatic cycles in relation to proper land use; even the word "conservation" had nothing of the meaning that it has for us today. For the sake of ourselves and those who will come after us, we must now set about repairing the mistakes of our forefathers. Conservation should, therefore, be made a part of everyone’s daily life. To know about the water table in the ground is just as important to us as a knowledge of the basic arithmetic formulas. We need to know why all watersheds need the protection of plant life and why the running current of streams and rivers must be made to yield their full benefit to the soil before they finally escape to the sea. We need to be taught the duty of planting trees as well as of cutting them. We need to know the importance of big, mature trees, because living space for most of man’s fellow creatures on this planet is figured not only in square measure of surface but also in cubic volume above the earth. In brief, it should be our goal to restore as much of the original beauty of nature as we can. It can be inferred from the third paragraph that earlier generations didn’t realize______.
一个国家的各级各类新闻媒体机构及其从事的大众传播工作的总和就是这个国家的____。
There seems never to have been a civilization without toys, but when and how they developed is unknown. They probably came about just to give children something to do.In the ancient world, as is today, most boys played with some kinds of toys and most girls with another. In societies where social roles are rigidly determined, boys pattern their play after the activities of their fathers and girls after the tasks of their mothers.. This is true because boys and girls are being prepared, even in play, to step into the roles and responsibilities of the adult world.What is remarkable about the history of toys is not so much how they changed over the centuries but how much they have remained the same. The changes have been mostly in terms of craftsmanship, mechanics, and technology. In Egypt, the Americas, China, Japan and among the Arctic (北极的) peoples, generally the same kinds of toys appeared. Variations depended on lo- cal customs and ways of life because toys imitate(模仿) their surroundings.Because toys can be generally regarded as a kind of art form, they have not been subject to technological leaps that characterize inventions for adult use. The progress from the wheel to the oxcart to the automobile is a direct line of ascent (进步). The progress from a rattle (拨浪鼓) used by a baby in 3,000 B.C. to one used by an infant today, however, is not characterized by inventiveness. Each rattle is the product of the artistic tastes of the times and subject to the limitations of available materials. Which of the following statements is true（）
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