正确答案: B
题目:请在第___________处填上正确答案.
解析:【答案】B【解析】句意为:制盐的一种办法就是将海水放在浅底的水池里直至水分完全蒸发。
学习资料的答案和解析:
根据以下材料,回答下面的题目。The FamiIvThe structure of a family takes different forms around the world and even in the same society.The family’S form changes as it adapts to changing social and economic influences.Until recently.the most common form in North America was the nuclear family,consisting of a married couple with their minor children.The nuclear family is an independent unit.It must be prepared to fend for itself.Individual family members strongly depend on one another.There is little help from outside the family in emergencies.Elderly relatives of a nuclear family are cared for only if it is possible for the family to do so.In North America,the elderly often do not live with the family;thev live in retirement communities and nursing homes.There are many parallels between the nuclear family in industrial societies.such as North America,and of families in societies such as that of the Inuits,who live in harsh environments.The nuclear family structure is well adapted to a life of mobility.In harsh conditions,mobility allows the family to hunt for food.For North Americans,the hunt for jobs and improved social status also requires mobility.The nuclear family was not always the North American standard. In a more agrarian time,the mall nuclear family was usually part of a larger extenged family.This might have included grandparents,mother and father,brothers and sisters,uncles,aunts,and cousins. In North America today,there is a dramatic rise in the number of single.parent households.Twice as many households in the United States are headed by divorced,separated,or never。married individuals as are comprised of nuclear families.The structure of the family,not just in North America,but throughout the world,continues to change as it adapts to changing conditions.Another good title for this passage would be
阅读材料,回答下面的题目。The New Technology ApplicationOn a more mundane level, third-generation mobile telephones, despite all the delays and the billions squandered on 3G licenses by telecom firms, are still expected to offer consumers high-speed, always on mobile internet access, complete with video, in the next few years.Rapidly proliferating "WiFi" networks already offer wireless access on a local basis. Tiny tracking chips called radio-frequency identification devices are being used as pet passports.Soon they will be small, powerful and cheap enough to be implanted into everything form humans to milkcartons recording and transmitting real-time medical data, or serving as a form of inventory control.Sensors of every kind, including video cameras, should also become much smaller and cheaper.Forrester Research, a technology consultancy, predicts that 14 billion such devices will be connected to the internet by 2005.How rapidly such new technology is introduced will depend on a number of factors the state of the economy, the supply of investment capital and the appetite of consumers for new products or services ! Fortunes will be made and lost many times over.But whatever happens, the power of computing and communications look set to continue to grow, and its price to fall, at a steady rate for the next few decades.That will make it possible, at least in rich countries, to record most human interactions, wherever and whenever they take place, and to store and analyze this ocean of data at low cost.For the sake of argument, this survey will assume that we are heading towards a networked society of ubiquitous, mobile Communication capable of constant monitoring.Whether this arrives in 20,30 or 40 years does not really matter.The point is that the destination seems not merely possible, but probable, so it is not toosoon to ask: What do we want this technology to do?The internet has already thrown up a host of legal and political conundrums, but, these are only a small foretaste of the dilemmas about privacy, security, intellectual property and the nature of government itself that will have to be faced over the coming decades.The debate has already begun. This survey will outline some of main issues, and speculate on the way they are likely to go. Radio-frequency identification devices__________.
回答下面的题目:Exercise Being Good or BadCan exercise be a bad thing? Sudden death during or soon after strenuous exertion on the squash court or on the army training grounds, is not unheard of. 51 trained marathon runners are not immune to fatal heart attacks. But no one knows just 52 common these sudden deaths linked to exercise are. The registration andinvestigation of such 53 is very patchy; only a national survey could determine the true 54 of sudden deaths in sports. But the climate of medical opinion is shifting in 55 of exercise, for the person recovering from a heart attack as 56 as the average lazy individual. Training can help the victim of a heart attack bylowering the 57 of oxygen the heart needs at any given level of work 58 the patient can do more before reaching the point where chest pains indicate a heart starved of oxygen. The question is, should middle-aged people, 59 .particular, be screened for signs of heart disease before 60 vigorous exercise?Most cases of sudden death in sport are caused by lethal arrhythmias in the beating of the heart, often in people 61 undiagnosed coronary heart disease. In North America 62 over 35 is advised to have a physical check-up and even an exercise electrocardiogram. The British, on the whole, think all this testing isunnecessary. Not many people die from exercise, 63 , and ECGs ( 心电图 ) are notoriously inaccurate. However, two medical cardiologists at the Victoria Infirmary in Glasgow, advocate screening by exercise ECG for people over 40, or younger people 64 at risk of developing coronary heart disease. Individuals showing a particular abnormality in their ECGs 65 , they say, a 10 to 20 times greater risk of subsequently developing signs of coronary heart disease, or of sudden death.第51题应选:
根据以下资料,回答下面的题目。 Oklahoma is an area often experiencing natural disasters.