The news about vitamins keeps getting worse. Many studies published in the last few years shows that a variety of popular supplements dont do anything to reduce the risk of developing heart disease, stroke or a variety of cancers. But what about multivitamins? These combination pills, which【C1】______10 to 30 vitamins and【C2】______, are the most popular supplements sold in America. A report published recently suggests they shouldnt be. The study【C3】______161,808 participants in the Womens Health Initiative, a long-term effort to【C4】______risk factors for cancer, heart disease and bone health in elderly women.【C5】______in the nationwide study included white, black, Asian and Native American women. They were followed for an average of nearly eight years.【C6】______, 41.5% of study participants took some version of a multivitamin. Those women were more likely to be white and college-educated, live in the West, exercise and have a lower body mass index. However, women who took multivitamins werent any more likely to【C7】______a diagnosis of breast, lung, stomach, and other cancers than were women who didnt take multivitamins. Nor were multivitamins in general helpful in【C8】______heart attacks, strokes or reducing the risk of death from any【C9】______during the study period. The research team did find one【C10】______benefit: The 3,741 women who took stress multivitamins—formulations【C11】______higher doses of several B vitamins along with an extra amount of vitamin C—were 25% less likely to have a heart attack. No other correlations between vitamins and health outcomes were statistically【C12】______. The study provides【C13】______evidence that multivitamin use has little or no【C14】______on the risk of common cancers, heart disease or total mortality in elderly women.【C15】______, researchers wondered, 'Why do millions of Americans use a daily multivitamin for【C16】______disease prevention when the supporting scientific data are weak?' Some physicians continue to【C17】______them for patients whose diets may have nutritional【C18】______. And since they dont require a prescription, many people simply【C19】______they are safe. But those assumptions may not be【C20】______, especially if people wind up overdosing on vitamins and minerals, the researchers wrote.
【C1】
A．generate
B．represent
C．contain
D．scrape

判断题通过总结教育教学经验，既能注意教育实践中感性认识的积累和总结，又能注意教育理论指导下教育实践材料的分析研究与理性升华，提高教师的教育科学研究水平。()

未分类题Mammals vary enormously in size, from weighing less than a penny to measuring more than three school buses in length. Some groups of mammals have become very large, such as elephants and whales,【C1】______others have always been small, like primates. A new theory developed by an international team, led by Jordan Okie,【C2】______an explanation for why and how【C3】______groups of organisms are able to evolve【C4】______sizes, whereas others are not. The research team【C5】______information on how quickly an individual animal grows and used it to【C6】______how large it may get【C7】______evolutionary time. Their research was published recently. The new theory developed from the observation that some animals【C8】______fast and die young, while others take their time and mature much later. 'Fast' animals-such as mice—breed very quickly, while humans mature slowly and are relatively older when they first have children. The theory【C9】______that those species that are relatively faster are more likely to evolve a large size quicker than slow species, and that their maximum size will be greater. The research team tested their theory using the【C10】______records of mammals over the last 70 million years, examining the maximum size of each mammal group【C11】______that time, including whales, elephants, seals and primates. They found that their theory was very well【C12】______. 'Primates have evolved very slowly, and never got bigger than 1,000 pounds,' said Okie, 'The【C13】______was true of whales, which evolved their large size at the fastest【C14】______recorded.' The theory also makes predictions about the relative risks of extinction for large animals【C15】______small. The maximum size of an animal is limited by the rate of mortality in the【C16】______. Because larger animals【C17】______breed less frequently than smaller animals,【C18】______the mortality rate doubles, the maximum size is predicted to be 16 times smaller. 'This is a really surprising【C19】______,' said Okie. 'It points to another reason why many of the large animals went【C20】______after the last Ice Age, and their high risk of extinction in modern environments.'【C1】A．becauseB．whileC．ifD．and

未分类题【C18】A．in thatB．despiteC．thereforeD．if

判断题重测信度也叫稳定性系数，是估计测验跨时间的一致性的指标。用同一种测验对同一组被试先后施测两次，被试两次测验分数间的相关系数即为重测信度。()

单项选择题有一台六极三相绕线式异步电动机，在f=50Hz的电源上带额定负载运行，其转差率为0.02，电动机的同步转速为( )。 A.900r min B.1200r min C.1000r min D.1400r min