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第三篇Iron DeficienciesE"的相关试题:
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第三篇
Iron Deficiencies
Experts have observed for years that endurance athletes,particularly females,frequently have iron deficiencies.Now a new study by a team of Purdue University researchers suggests that even moderate exercise may lead to reduced iron in the blood of women.
"We found that women who were normally inactive and then started a program of moderate exercise showed evidence of iron loss,"says Roseanne M.Lyle,associate professor at Purdue.Her study of 62 formerly inactive women who began exercising three times a week for six months was published in the journal Medicine & Science in Sports & Exercise."Women who consumed additional meat or took iron supplements were able to bounce back,"she notes."But the new exercisers who followed their normal diet showed a significant decrease in iron levels."
Iron deficiency is very common among women in general,affecting one in four female teenagers and one in five women aged 18 to 45,respectively.But the ratio is even greater among active women,affecting up to 80 percent of female endurance athletes.This means,Lyle says,that"too many women ignore the amount of iron they take in."
Women of childbearing age are at greatest risk,since their monthly bleeding is a major source of iron loss.Plus,many health-conscious women increase their risk by rejecting red meat,which contains the most easily absorbed form of iron.And because women often restrict their diet in an effort to control weight,they may not consume enough iron-rich food,and are liable to experience a deficiency.
"The average woman takes in only two thirds of the recommended daily allowance of iron," notes another expert."For a woman who already has a poor iron status,any additional iron loss from exercise may be enough to tip her over the edge into a more serious deficiency,"notes the expert. Exercise can result in iron loss through a variety of mechanisms.Some iron is lost in sweat,and,for unknown reasons,intense endurance exercise is sometimes associated with bleeding of the digestive system.
The best sources of iron,and the only sources of the form of iron most readily absorbed by the body,are meat,chicken,and fish.Good sources of other forms of iron include dates,beans,and some leafy green vegetables.
Which group of women will possibly have iron loss?
A.one in four women aged 18 to 45.
B.one in five female teenagers.
C.80 percent of female endurance athletes.
D.80 percent of active women.
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第三篇
People have been painting pictures for at least 30,000 years.The earliest pictures were painted by people who hunted animals.They used to paint pictures of the animals they wanted to catch and kill.Pictures of this kind have been found on the walls of caves in France and Spain.No one knows why they were painted there.Perhaps the painters thought that their pictures would help them to catch these animals.Or perhaps human beings have always wanted to tell stories in pictures.
About 5,000 years ago,the Egyptians and other people in the Near East began to use pictures as kind of writing. They drew simple pictures or signs to represent things and ideas,and also to represent the sounds of their language.The signs there people used became a kind of alphabet.
The Egyptians used to record information and to tell stories by putting picture-writing and pictures together. When an important person died,scenes and stories from his life were painted and carved on the walls of the place where he was buried.Some of these pictures are like modern comic strip stones.It has been said that Egypt is the home of the comic strip.But for Egyptians,pictures still had magic power. So they did not try to make their way of writing simple.The ordinary people could not understand it.
By the year 1000 BC,people who lived in the area around the Mediterranean Sea had developed a simpler system of writing. The signs they used were very easy to write,and there were fewer of them than in the Egyptian system.This was because each sign,or letter,represented only one sound in their language.The Greeks developed this system and formed the letters of the Greek alphabet.The Romans copied the idea and the Roman alphebet is now used all over the world.
These days,we can write down a story,or record information,without using pictures.But we still need pictures of all kinds:drawing,photographs,signs and diagrams.We find them everywhere:in books and newspapers,in the street,and on the walls of the places where we live and work.Pictures help us to understand and remember things more easily,and they can make a story much more interesting.
In the last paragraph,the author thinks that pictures______.
A.should be made comprehensible
B.should be made interesting
C.are of much use in our life
D.have disappeared from our life
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第三篇
Americans still have been gaining weight,although they have cut their average fat intake from 36 to 34 percent of their total diets in the past 15 years.Indeed,cutting fat to control or lose weight makes sense. Fat has nine calories per gram. Protein and carbohydrates（碳水化合物）which break down into amino acids and simple sugars respectively,have just four. Moreover,the body uses fewer calories to metabolize（新陈代谢）fat than it does to metabolize other foods.
But cutting fat from your diet doesn't necessarily mean your body won't store fat. For example, between nonfat and regular cookies,there's trivial difference in calories because manufacturers make up for the loss of fat by adding sugar. Low-fat crackers,soups and dressings can also be just as high in calories as richer versions.No matter where the calories come from,overeating will still cause weight gain.The calories from fat just do it a little quicker. A Wisconsin computer programmer who decided with a diet coach to eat only 40 grams of fat a day learned the lesson firsthand.He wasn't losing weight.Then he showed his food diary to his coach and revealed he'd been eating half a pound of jelly beans a day."They don't have any fat,"he explains.But they had enough sugar to keep him from losing an ounce.
Nonfat foods become add-on foods.When we add them to our diet,we actually increase the number of calories we eat per day and gain weight. That was born out in a Pennsylvania State University study.For breakfast,Prof. Barbara Rolls gave two groups of women yogurt that contained exactly the same amount of calories.One group's yogurt label said"high fat”一the other,"low fat". The"low fat"yogurt group ate significantly more calories later in the day than the other group. "People think they've saved fat and can indulge themselves later in the day with no adverse consequences,"says Richard Mattes,a nutrition researcher at Purdue University."But when they do that,they don't compensate very precisely,and they often end up overdoing it."
What can be inferred from the passage?
A.To avoid being overweight,people should eat nonfat food.
B.Nonfat and regular food have no difference in calories.
C.Americans think it necessary to count calories of food.
D.We can eat nonfat food as much as we like.
