题目

请阅读短文,完成此题。Move over Methuselah. Future generations could be living well into their second century andstill doing Sudoku, if life expectancy predictions are true. Increasing by two years every decade,they show no signs of flattening out. Average lifespan worldwide is already double what it was 200years ago. Since the 1980s, experts thought the increase in life expectancy would slow down andthen stop, but forecasters have repeatedly been proved wrong.The reason behind the steady rise in life expectancy is "the decline in the death rate of theelderly", says Professor Tom Kirkwood from Newcastle University. He maintains that our bodies areevolving to maintain and repair themselves better and our genes are investing in this process to putoff the damage which will eventually lead to death. As a result, there is no ceiling imposed by thereahties of the ageing process."There is no use-by-date when we age. Ageing is not a fixed biological process," Tom says.A large study of people aged 85 and over carried out by Professor Kirkwood discovered that there were a remarkable number of people enjoying good health and independence in their late 80s and beyond. With people reaching old age in better shape, it is safe to assume that this is all due to better eating habits, living conditions, education and medicine.There are still many people who suffer from major health problems, but modem medicine means doctors are better at managing long-term health conditions like diabetes, high blood pressure and heart disease."We are reaching old age with less accumulative damage than previous generations. We are less damaged," says Professor Kirkwood. Our softer lives and the improvements in nutrition and healthcare have had a direct impact on longevity.Nearly one-in-five people currently in the UK will live to see their lOOth birthday, the Office for National Statistics predicted last year. Life expectancy at birth has continued to increase in the UK--from 73.4 years for the period 1991 to 1993 to 77.85 years for 2007 to 2009. A report in Science from 2002 which looked at life expectancy patterns in different countries since 1840 concluded that there was no sign of a natural limit to life.Researchers Jim Oeppen and Dr. James Vaupel found that people in the country with the highest life expectancy would live to an average age of 100 in about six decades. But they stoppedshort of predicting anything more."This is far from eternity: modest annual increments in life expectancy will never lead toimmortality," the researchers said.We do not seem to be approaching anything like the limits of life expectancy, says Professor David Leon from the London School of Hygiene and Tropical Medicine. "There has been no flattening out of the best of the best--the groups which everyone knows have good life expectancy and low mortalit_y"he says.These groups, which tend to be in the higher social and economic groups in society, can live for several years longer than people in lower social groups, prompting calls for an end to inequalities within societies.Within populations, genes also have an important role to play in determining how long we could survive for---but environment is still the most important factor.It is no surprise that healthy-living societies like Japan have the highest life expectancies in the world. But it would still be incredible to think that life expectancy could go on rising forever. "I would bet there will be further increases in life expectancy and then it will probably begin to slow," says Tom, "but we just donTt know."Which statement below is TRUE concerning life expectancy according to the passage?查看材料
A.Life expectancy goes on rising forever.B.There could be further increases in life expectancy.C.Life expectancy has slowed down since 1980s and it will stop.D.Life expectancy in Japan doubles what it was 200 years ago.

答案
查看答案
相关试题
根据题目要求完成下列任务,用中文作答。以下是两位教师为学生布置的作业:?Teacher 1Step 4: Homework1. Write new words and phrases on the notebook.2. Finish exercise 3 on Page 21. (Text book)3. Finish exercises on Page 20-24. (Exercise book)Teacher 2Step 4: Homework1. Find some relative information about today's lesson on the Interact.2. Share your findings with your group members and present to the whole students next class.请根据所给材料回答下面3个问题。(1)分析两位教师布置作业的特点,并指出其不足之处。(10分)(2)教师的作业设计有哪些注意事项。(至少从四个方面)(12分)(3)列举几种常见的英语作业形式。(8分)
请阅读短文,完成此题。When we analyze the salt salinity(盐溶度 ) of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by-evaporation, or decreased by the addition of fresh water by precipitation.Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.Which of the following is not the cause of the decrease in the oceanic salinity?查看材料
A.Precipitation.B.Rain and snow.C.Formation of ice.D.Addition of water by rivers.
请阅读短文,完成此题。When we analyze the salt salinity(盐溶度 ) of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by-evaporation, or decreased by the addition of fresh water by precipitation.Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.This passage mainly tells us about__________.查看材料
A.the analysis of the salinity of ocean watersB.the causes of the variation in oceanic salinityC.the importance of the changes in oceanic salinityD.the different forms of salts in ocean waters
请阅读短文,完成此题。When we analyze the salt salinity(盐溶度 ) of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by-evaporation, or decreased by the addition of fresh water by precipitation.Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.The purpose of mentioning the Weddell Sea is__________.查看材料
A.to give an example of cold-water salinityB.to point out the location of deep watersC.to make a comparison between hot-water salinity and cold-water salinityD.to show that the water in the Weddell Sea varies in salinity from place to place
请阅读短文,完成此题。When we analyze the salt salinity(盐溶度 ) of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by-evaporation, or decreased by the addition of fresh water by precipitation.Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.Which of the following statements is TRUE according to the passage?查看材料
A.Oceanic salinity has great effect on sea life.B.Many factors combine to cause changes in oceanic salinity.C.The movement of the water is related to the amount of salt.D.The temperature of the water has much to do with the oceanic salinity.
最新解答的试题
提出现代生物-心理-社会医学模式是()

A.恩格尔B.波特C.托马斯·帕茨瓦尔D.比彻尔E.桑德斯
付款人在进行付款时无()

A.形式审查义务

B.实质审查义务

C.附带审查义务

D.票据外有关事项的审查义务
根据《公司法》的规定,有限责任公司下列人员中,可以提议召开股东会临时会议的是()。
A.总经理B.人数过半数的股东C.监事会主席D.人数为半数的董事
关于股份有限公司中的监事会,下列说法错误的是()

A.监事会负责提议聘请或更换外部审计机构B.监事会主席和副主席由全体监事过半数选举产生C.监事会中的职工代表的比例不得低于三分之一D.监事会应至少每6个月召开一次会议
三北精神的科学内涵