2017年9月21日雅思阅读考试机经精彩内容不要错过，很多考生都觉得雅思阅读因为文章比较长所以答题时间觉得不够充分，有了今天的2017年9月21日雅思阅读考试机经详细内容说不定可以帮助到大家，一起看看吧！

　　2017年9月21日雅思阅读考试机经内容如下：

　　Hibernation 动物

　　重复年份 20141220 20120512 20100520

　　题材 动物

　　题型 单选+summary+判断题

　　文章大意 主要讲了动物冬眠的情况等。

　　Hibernation is a state of inactivity and metabolic depression in endotherms. Hibernation refers to a season of heterothermy that is characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Although traditionally reserved for "deep" hibernators such as rodents, the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than based on absolute body temperature decline. Many experts believe that the processes of daily torpor and hibernation form a continuum and utilize similar mechanisms. The equivalent during the summer months is known as aestivation. Some reptile species (ectotherms) are said to brumate, or undergo brumation, but any possible similarities between brumation and hibernation are not firmly established. Some insects, such as the wasp Polistes exclamans, hibernate by aggregating together in groups in protected places called hibernacula.

　　Often associated with low temperatures, the function of hibernation is to conserve energy during a period when sufficient food is unavailable. To achieve this energy saving, an endotherm will first decrease its metabolic rate, which then decreases body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual's body condition.

　　Before entering hibernation, animals need to store enough energy to last through the entire winter. Larger species become hyperphagic and eat a large amount of food and store the energy in fat deposits. In many small species, food caching replaces eating and becoming fat.Some species of mammals hibernate while gestating young, which are either born while the mother hibernates or shortly afterwards.

　　For example, the female polar bear goes into hibernation during the cold winter months to give birth to her offspring. She loses 15–27% of her pre-hibernation weight and uses stored fats for energy during times of food scarcity, or hibernation. It is evident that pregnant female polar bears significantly increase body mass prior to hibernation, and this increase is further reflected in the weight of their offspring. The fat accumulation prior to hibernation in female polar bears enables them to provide a sufficient and warm, nurturing environment for their newborns

　　Newly Hatched birds 动物

　　Fluoridation in the water 医疗健康

　　Coastal sculpture 艺术

　　Trade 发展史 20160109B 20120728

　　Children and robot 科技

　　Culture and Communication人文社科

　　Ancient Greek Coins 人文社科

　　Darkside of Technological Boom 科技

　　Children's adults 文学

　　Expert in musician 人文社科

　　Skink in New Zealand 动物

　　Solving an Arctic Mystery 人文社科 20160521 20141025

　　Aquaculture in New Zealand农业

　　The meaning of history study 人文社科

　　Birds intelligence 动物

　　Ocean power 能源

　　Who should look after the child? 人文社科

　　Paper money 发展史

　　The tuatara-past and future 动物

　　Gesture 人文社科

　　Voynich manuscript 考古

　　Food Addictive 工业

　　Japan's ancient pottery 历史

　　Fish communications 动物

　　New Zealand Home Textile Craft 人文社科

　　Sweet Trouble–Australia sugarcane industry农业

　　The Grimme Fairy Tale 人文社科

　　We have star performers 商业管理

　　Blind to Change 心理学

　　Tick Tock Body clock 生物 20161013 20121013

　　The importance of being playful 人文社科

　　When did music begin? 艺术 20160528 20130216

　　Dust and American 环保

　　Human Rights to animal 人文社科

　　The power of music 艺术 20160109A 20131212*

　　Odd and curious money 人文社科

　　The history of Russian Ballet

　　Unique golden textile 工业

　　Consumer advertisement 商业管理

　　Australia Parrots 动物

　　Egypt‘s Sunken Treasures考古 20150509 20120331

　　Alcohol fuel in England 能源

　　2017年9月21日雅思阅读考试机经详细内容就是这些，考试的时候不要太紧张，轻松进考场对考试也是有一定帮助的，更多雅思考试资讯请继续关注环球教育雅思频道。