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Scientists have discovered a new kind of invisible ink. It’s called water. And all you need for this secret-messaging ink to work is to write with it on a super-hi-tech piece of paper coated with special chemicals. 1. It shows up darker than the surrounding paper under UV(紫外线的) light.
When the message has been read and needs to be hidden again, get out your hairdryer, and blow some warm air on the paper. 2.
Using hot air from a hairdryer for 15-30 seconds, you were able to reuse the special paper up to 30 times because the heat reorganized the chemical structure of the paper coating. 3.
The invention was made by a group of scientists in China, led by Qiang Zhao of the Institute of Advanced Materials, Nanjing University of Posts and Telecommunications.
Although much of modern communication is digital(数码的), there are still some situations in which it is important to send messages on a piece of paper, such as when the people don’t have Internet. 4. But the problem has always been how to get rid of a message once it has been shown so no one else can read it.
5.. To use it, write with the lemon juice on ordinary paper, iron(熨) the paper with a hot iron and the hidden message will appear. The downside(缺点) is that the paper has to be destroyed to hide the message so no one else can read it.
A.How to make the invisible ink? Follow the steps.
B.Invisible inks have long been used to send secret messages.
C.Without the heat, the message stayed visible for up to three months.
D.Previously, the most readily available invisible ink was lemon juice.
E.Shine a UV light on the coated paper and the water message becomes visible.
F.Then the message will be gone and the paper can be reused, which keeps costs low.
G.Putting water on the paper broke up the structure of the chemicals it was coated with.
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A healthy amount of sunshine may be the secret to staying young. British scientists have discovered.
Vitamin D is produced naturally by the skin in response to (对…的反应) sunlight and may help to slow the ageing process and protect against heart disease, according to the study.
Researchers from King's College London studied 2,160 women aged between 18 and 79, looking at their telomeres-a biological marker of ageing found in DNA. As people get older, their telomeres get shorter and they become more susceptible (易受伤害的) to certain illnesses.
But the study found women with high levels of vitamin D had comparatively longer telomeres-a sign of being biologically younger and healthier.
The study suggests vitamin D may help to slow down the ageing process of DNA, and therefore the ageing process as a whole.
Lead researcher Dr Brent Richards said, "These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D." This could help to explain how vitamin D has a protective effect on many ageing related diseases, such as heart disease and cancer."
Professor Tim Spector, a co-author of the report, added, " Although it might sound absurd(荒唐的), it's possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process.
Vitamin D made by the action of sunlight on the skin accounts for 90 percent of the body's supply, but lower levels can also be got through food such as fish, eggs and breakfast cereals(粥).
Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease.
1.A certain amount of sunshine helps people stay young because _________.
A. people feel happy and energetic in the sun
B. vitamin D may help to slow the ageing process
C. sunshine protects people against heart disease
D. vitamin D makes one's skin look young and healthy
2.From Brent Richards, we know that ________.
A. sunlight causes skin cancer to people with high level of vitamin D
B. the study generally has a healthy effect on the general ageing process
C. the higher levels of vitamin D people have, the more slowly people may age
D. vitamin D can only be got from fish, eggs and breakfast cereals
3.What can we infer from the passage?
A. Sunlight does more good than harm to our health.
B. Telomeres are important as they are signs of ageing of the DNA.
C. Sunlight can be dangerous as it causes skin cancer.
D. Vitamin D can also be gained from food.
4.What is the best title of the passage?
A. Secret of Staying Young
B. Sunlight and Vitamin D
C. Vitamin D Helps Slow Ageing
D. Sunlight and Health
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A healthy amount of sunshine may be the secret to staying young. British scientists have discovered.
Vitamin D is produced naturally by the skin in response to(对…的反应) sunlight and may help to slow the ageing process and protect against heart disease, according to the study.
Researchers from King’s College London studied 2,160 women aged between 18 and 79, looking at their telomeres--- a biological marker of ageing found in DNA. As people get older, their telomeres get shorter and they become more susceptible(易受伤害的) to certain illnesses.
But the study found women with high levels of vitamin D had comparatively longer telomeres--- a sign of being biologically younger and healthier.
The study suggests vitamin D may help to slow down the ageing process of DNA, and therefore the ageing process as a whole.
Lead researcher Dr Brent Richards said, “These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D.” This could help to explain how vitamin D has a protective effect on many ageing related diseases, such as heart disease and cancer.”
Professor Tim Spector, a co-author of the report, added, “Although it might sound absurd
(荒唐的), it’s possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process.”
Vitamin D made by the action of sunlight on the skin accounts for 90 percent of the body’s supply, but lower levels can also be got through food such as fish, eggs and breakfast cereals(粥).
Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease.
1. A certain amount of sunshine helps people stay young because _____.
A. people feel happy and energetic in the sun
B. sunshine protects people against heart disease
C. vitamin D makes one’s skin look young and healthy
D. vitamin D may help to slow the ageing process
2.From Brent Richards, we know that _____.
A. sunlight causes skin cancer to people with high level of vitamin D
B. the study generally has a healthy effect on the general ageing process
C. vitamin D can only be got from fish, eggs and breakfast cereals
D. the higher levels of vitamin D people have, the more slowly people may age
3.What can we infer from the passage?
A. Telomeres are important signs of ageing of the DNA.
B. Sunlight can be dangerous as it causes skin cancer.
C. Sunlight does a great deal of good to our health.
D. Vitamin D can also be gained from food.
4. What is the best title of the passage?
A. Secret of Staying Young B. Vitamin D Helps Slow Ageing
C. Sunlight and Vitamin D D. Sunlight and Health
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A healthy amount of sunshine may be the secret to staying young. British scientists have discovered.
Vitamin D is produced naturally by the skin in response to(对…的反应) sunlight and may help to slow the ageing process and protect against heart disease, according to the study.
Researchers from King’s College London studied 2,160 women aged between 18 and 79, looking at their telomeres--- a biological marker of ageing found in DNA. As people get older, their telomeres get shorter and they become more susceptible(易受伤害的) to certain illnesses.
But the study found women with high levels of vitamin D had comparatively longer telomeres--- a sign of being biologically younger and healthier.
The study suggests vitamin D may help to slow down the ageing process of DNA, and therefore the ageing process as a whole.
Lead researcher Dr Brent Richards said, “These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D.” This could help to explain how vitamin D has a protective effect on many ageing related diseases, such as heart disease and cancer.”
Professor Tim Spector, a co-author of the report, added, “ Although it might sound absurd(荒唐的), it’s possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process.
Vitamin D made by the action of sunlight on the skin accounts for 90 percent of the body’s supply, but lower levels can also be got through food such as fish, eggs and breakfast cereals(粥).
Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease.
1.A certain amount of sunshine helps people stay young because _________.
A. vitamin D may help to slow the ageing process
B. sunshine protects people against heart disease
C. vitamin D makes one’s skin look young and healthy
D. people feel happy and energetic in the sun
2.From Brent Richards, we know that ________.
A. sunlight causes skin cancer to people with high level of vitamin D
B. the higher levels of vitamin D people have, the more slowly people may age
3.What can we infer from the passage?
A. Telomeres are important as they are signs of ageing of the DNA.
B. Sunlight can be dangerous as it causes skin cancer.
C. Sunlight does more good than harm to our health.
D. Vitamin D can only be gained from food.
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It is believed that a new kind of drug ______ by the scientists and they are hopeful that they will succeed in a few months.
A. has been developed B. is being developed
C. is developing D. has developed
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It is believed that a new kind of drug _____ by the scientists and they are hopeful that they will succeed in a few months．
A．has been developed B．is being developed
C．is developing D．has developed
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For many years, Bruce Bexler dreamed of going where no human had gone before. He wanted to cut a path through unexplored lands and discover rare species.
That might sound like an impossible dream, but Bexler turned it into a reality.
In December 2015, he and a team of Australian scientists explored an isolated rainforest on the island of New Guinea. They were the first people to enter the region. “As time was limited, we were dropped in by helicopter. Once we were on the ground, there were no trails anywhere; it was really hard to get around,” Bexler says.
Within minutes of landing, the team spotted a black chicken-like bird with strange orange skin hanging from its neck. The scientists soon determined that the unusual creature was a type of honeyeater — the first new bird species to be sighted on New Guinea in 60 years.
The honeyeater wasn’t the only surprise for the scientists. They discovered more than 40 previously unknown plant and animal species — 13 birds of paradise, 20 frogs, four butterflies, and five palms. “We were like kids in a candy store,” Bexler recalls. “Everywhere we looked, we saw amazing things we had never seen before.”
The newfound species didn’t shy away from the scientists. Two long-nosed echidnas — primitive egg-laying mammals — let the visitors pick them up and take them back to camp to study them.
Bexler thinks the animals weren’t frightened because they had never seen humans before. “In almost all parts of New Guinea, animals are hunted for food, and because of this, they are very cautious of people,” he explains. “This area gives scientists a place where they can go to study the behaviors of animals that have not yet learned to be afraid of people.”
Scientists believe the area is probably the largest untouched forest in Asia. Bexler and his team did not have enough time to study the area completely. They hope to return to record more undiscovered species. “We just scratched the surface,” Bexler says. “Anyone who goes there will come back with a mystery.”
1.Which word best describes Bruce Bexler?
A.Modest. B.Adventurous.
C.Optimistic. D.Confident.
2.What does Bruce Bexler mean in Paragraph 5 when he says the scientists “were like kids in a candy store”?
A.They didn’t have enough food and were hungry.
B.They were very excited about what they saw.
C.They were behaving like naughty children.
D.They knew that if they kept searching, they’d find sugar.
3.Why did some of the animals allow the scientists to pick them up?
A.The scientists seemed to be very friendly.
B.The scientists were good at handling animals.
C.The animals had been well-trained by the local people.
D.The animals had no experience or fear of people.
4.What can we conclude about the area Bruce Bexler explored?
A.The best way to explore the area is by helicopter.
B.The area has not been visited by scientists for many years.
C.The area still contains many plants and animals unknown to science.
D.The locals are unwilling to allow the scientists to enter the deep woods.
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A new kind of drug ___ ___ to cure H7N9 bird flu by the scientists and they are hopeful that they will succeed in a couple of weeks.
A. has been developed B. is being developed C. is developing D. has developed
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Scientists may have found a way to reduce shortage of type O blood. Type O is the kind of blood that hospitals most often need. What the researchers are testing is an easier way to make type O blood out of other kinds of blood.
There are four main kinds of blood. Most people born with one of these four: Type A,Type B, Type AB or Type O. Type O can be safely given to anyone. So it is commonly used when a person is injured or sick and has to have blood.
The differences among blood types are linked to whether or not red blood cells contain certain kinds of sugar molecules(分子). These molecules are found on the surface of the cells.They are known as antigens (抗原). These antigens are found with type A, B and AB blood but not with type O.
More than twenty-five years ago, scientists found that the antigens could be removed to create what they called universal-type cells. They could be removed with chemicals called enzymes(酶). But large amounts of enzymes were required to make the change.
Doctor Henrik Clausen of the University of Copenhagen in Denmark led the study. The next step, he says, is to complete safety tests. The team is working with the American company ZymeQuest to test the new method. If it meets safety requirements(*k)and is not too costly,it could become a widely used life-saving tool to increase the supply of universal blood.
1.How do scientists deal with the problem of lacking type O blood?
A.Hope more people to donate type O blood.
B.Make the most of the present type O blood.
C.Develop new ways of using type O blood.
D.Make type O blood out of other kinds of blood.
2.What make people have different kinds of blood?
A.Sugar molecules in red blood cells.
B.People's different living conditions.
C.Peoples various immune systems.
D.The variety of peoples cells and genes.
3.What can we infer from the text?
A.Type O blood can be safely given to anyone
B.Antigens could easily be removed to create universal blood.
C.A Danish company wanted to involve itself in studying blood.
D.The new method is not safe enough to be put into use in hospitals now.
4.What is the best title for the text?
A.Four different kinds of blood
B.A new way to make type O blood
C.The latest research on blood type
D.Find the proper type of blood
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Paragraph 1
Scientists have learned a lot about the kinds of food people need. They say that there are several kinds of food that people should eat every day. They are: (1) green and yellow vegetables of all kinds. (2) citrus(柑桔) fruits and tomatoes; (3) potatoes and other fruits and vegetables; (4) meat of all kinds, fish and eggs; (5) milk and foods made from milk; (6) bread or cereal(谷类), rice is also in this kind of food; (7) butter, or something like butter.
Paragraph 2
People in different countries and different places of the world eat different kinds of things. Foods are cooked and eaten in many different kinds of ways. People in different countries eat at different times of the day. In some places people eat once or twice a day; in other countries people eat three or four times a day. Scientists say that none of the differences is really important. It doesn’t matter whether foods are eaten raw(生的) or cooked, canned or frozen. It doesn’t matter if a person eats dinner at 4 o’clock in the afternoon or at eleven o’clock at night. The important thing is what you eat every day.
Paragraph 3
There are two problems, then, in feeding the large number of people on earth. The first is to find some ways to feed the world’s population so that no one is hungry.
The second is to make sure that people everywhere have the right kinds of food to make them grow to be strong and healthy.
1.According to the scientists, which of the following groups of food is the healthiest for your lunch?
A．chicken, apples, cereal, cabbages B．potatoes, carrots, rice, bread
C．oranges, bananas, fish, tomatoes D．beef, pork, fish, milk
2.It is important for people to eat _______.
A．three times a day
B．dinner at the right time
C．cooked food all the day
D．something from each of the seven kinds of food every day
3.Which of the following is NOT true?
A．People in some places don’t have enough to eat.
B．There are too many people in the world.
C．One of the problems is that no one is hungry.
D．The scientists are trying to make people grow to be strong and healthy.
4.If there is Paragraph 4, what do you think is going to be talked about?
A．When people should eat.
B．What to do with the two problems.
C．How to cook food in different ways.
D．Why people eat different kinds of food.