People have been wondering why elephants do not develop cancer even though they have lifespans (寿命) that are similar to humans, jiving for around 50 to 70 years.
Now scientists believe they know why. A team at the University of Chicago, US has found that elephants carry a large number of genes that stop tumors (肿瘤) developing. To be precise, they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy.
According to the research, the extra copies of the gene improved the animal’s sensitivity to DNA damage, which lets the cells quickly kill themselves when damaged before they can go on to form deadly tumors.
“An increased risk of developing cancer has stood in the way of the evolution of large body sizes in many animals,” the study author Dr Vincent Lynch told The Guardian. If every living cell has the same chance of becoming cancerous (癌变的), large creatures with a long lifespan like whales and elephants should have a greater risk of developing cancer than humans and mice. But across species, the risk of cancer does not show a connection with body mass.
This phenomenon was found by Oxford University scientist Richard Peto in the 1970s and later named “Peto’s paradox (悖论)”. Biologists believe it results from larger animals using protection that many smaller animals do not. In the elephant’s case, the making of TP53 is nature’s way of keeping this species alive.
The study also found that when the same genes were brought to life in mice, they had the same cancer resistance as elephants. This means researchers could use the discovery to develop new treatments that can help stop cancers spreading or even developing in the first place.
“Nature has already figured out how to prevent cancer,” said Joshua Schiffman, a biologist at the School of Medicine, University of Utah, US. “It’s up to us to learn how different animals deal with the problem so that we can use those strategies to prevent cancer in people.”
1.Why are elephants unlikely to develop cancer?
A.They have a rather large body size.
B.Their genes suffer no DNA damage.
C.Certain genes in their body kill existing tumors.
D.They carry many genes to prevent tumors developing.
2.According to the passage, what has been a risk in the evolution of large animals?
A.Deadly tumors. B.The huge body mass.
C.Cells killing themselves. D.Sensitivity to DNA damage.
3.What does the underlined part “This phenomenon” in Paragraph 5 probably refer to?
A.Larger animals have protection from TP53.
B.The risk of cancer is not related to body size.
C.Larger animals suffer the same risk of cancer as smaller ones.
D.The larger animals are, the bigger risk of cancer they will have.
4.What can be concluded from the passage?
A.Depending on nature is surely enough to fight against cancer.
B.The TP53 genes have proved useful in stopping cancer in people.
C.Humans are expected to prevent cancer with the making of TP53.
D.The extra copies of elephants, genes are used to cure cancer patients.
高二英语阅读理解中等难度题
People have been wondering why elephants do not develop cancer even though they have lifespans (寿命) that are similar to humans, jiving for around 50 to 70 years.
Now scientists believe they know why. A team at the University of Chicago, US has found that elephants carry a large number of genes that stop tumors (肿瘤) developing. To be precise, they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy.
According to the research, the extra copies of the gene improved the animal’s sensitivity to DNA damage, which lets the cells quickly kill themselves when damaged before they can go on to form deadly tumors.
“An increased risk of developing cancer has stood in the way of the evolution of large body sizes in many animals,” the study author Dr Vincent Lynch told The Guardian. If every living cell has the same chance of becoming cancerous (癌变的), large creatures with a long lifespan like whales and elephants should have a greater risk of developing cancer than humans and mice. But across species, the risk of cancer does not show a connection with body mass.
This phenomenon was found by Oxford University scientist Richard Peto in the 1970s and later named “Peto’s paradox (悖论)”. Biologists believe it results from larger animals using protection that many smaller animals do not. In the elephant’s case, the making of TP53 is nature’s way of keeping this species alive.
The study also found that when the same genes were brought to life in mice, they had the same cancer resistance as elephants. This means researchers could use the discovery to develop new treatments that can help stop cancers spreading or even developing in the first place.
“Nature has already figured out how to prevent cancer,” said Joshua Schiffman, a biologist at the School of Medicine, University of Utah, US. “It’s up to us to learn how different animals deal with the problem so that we can use those strategies to prevent cancer in people.”
1.Why are elephants unlikely to develop cancer?
A.They have a rather large body size.
B.Their genes suffer no DNA damage.
C.Certain genes in their body kill existing tumors.
D.They carry many genes to prevent tumors developing.
2.According to the passage, what has been a risk in the evolution of large animals?
A.Deadly tumors. B.The huge body mass.
C.Cells killing themselves. D.Sensitivity to DNA damage.
3.What does the underlined part “This phenomenon” in Paragraph 5 probably refer to?
A.Larger animals have protection from TP53.
B.The risk of cancer is not related to body size.
C.Larger animals suffer the same risk of cancer as smaller ones.
D.The larger animals are, the bigger risk of cancer they will have.
4.What can be concluded from the passage?
A.Depending on nature is surely enough to fight against cancer.
B.The TP53 genes have proved useful in stopping cancer in people.
C.Humans are expected to prevent cancer with the making of TP53.
D.The extra copies of elephants, genes are used to cure cancer patients.
高二英语阅读理解中等难度题查看答案及解析
Have you ever wondered why there are so many skin colors in the world? Do you know why people living in particular areas usually have a certain color? Biology and history are the two reasons for this.
Skin contains something called melanin, which determines a person’s skin color. The more melanin a person has, the darker his or her skin will be. The amount of and the production of melanin are controlled by genetics, but can be affected by other things, such as sunlight. If a person lives in a place with less sunlight, a person’s body will produce less melanin, making the skin lighter.
Skin color is also affected by another source ---- vitamin D. humans all need vitamin D to build bones. People can get it by eating foods such as fish and milk, or from sunlight, so sunlight absorbed by melanin cannot be used for vitamin D production. Therefore, a dark—skinned person will produce less vitamin D than a light—skinned person when they received the same amount of sunlight.
The connection between vitamin D production and skin color is clear when we look at evolution. The earliest humans lived in Africa, their dark skin produced less vitamin D because of their dark skin. As a result, their skin made less melanin, so they could get enough sunlight to produce vitamin D. their skin gradually got lighter and they lost hair. Now, people living in areas with strong sunlight like Africa, have darker skin, while people living in other areas have lighter skin. The exception to this is the Inuit, who live in a place with little sunlight, but have dark skin because they eat a lot of fish and have enough vitamin D.
Evolution has given us a rainbow of skin colors. Humans have always had melanin to determine our skin color. What has changed through history is the environment where we have lived. This has in turn changed our melanin production, and eventually, skin color.
| Brief __71__ | People living in a particular __72__ usually have the same skin color and there are many different skin colors in the world. |
| Reason for skin color | The reasons for different skin colors mainly__73__ in biology and history. |
| Biology reasons | The amount of melanin, by which a person’s skin color is__74__ , varies from people to people. The more melanin a person has, the __75__ his or her skin will be. Vitamin D is another source__76__ skin color. Vitamin D is necessary for humans to build bones. Sunlight contributes to vitamin D in the skin. |
| Historical reasons | The earliest people in Africa had dark skin with hair covering it because the sunlight is very strong. When they moved to places where they could not get enough sunlight to__77__ vitamin D, their skin color became lighter. Generally speaking, people in areas with strong sunlight, have darker skin __78__ people in other areas have lighter skin. |
| __79__ | Melanin__80__an important role in our skin color. With our living environment changing, melanin production is changed, which leads to the changes in our skin color. |
高二英语其他题中等难度题查看答案及解析
Have you ever wondered why there are so many skin colors in the world? Do you know why people living in particular areas usually have a certain color? Biology and history are the two reasons for this.
Skin contains something called melanin, which determines a person’s skin color. The more melanin a person has, the darker his or her skin will be. The amount of and the production of melanin are controlled by genetics, but can be affected by other things, such as sunlight. If a person lives in a place with less sunlight, a person’s body will produce less melanin, making the skin lighter.
Skin color is also affected by another source ---- vitamin D. humans all need vitamin D to build bones. People can get it by eating foods such as fish and milk, or from sunlight, so sunlight absorbed by melanin cannot be used for vitamin D production. Therefore, a dark—skinned person will produce less vitamin D than a light—skinned person when they received the same amount of sunlight.
The connection between vitamin D production and skin color is clear when we look at evolution. The earliest humans lived in Africa, their dark skin produced less vitamin D because of their dark skin. As a result, their skin made less melanin, so they could get enough sunlight to produce vitamin D. their skin gradually got lighter and they lost hair. Now, people living in areas with strong sunlight like Africa, have darker skin, while people living in other areas have lighter skin. The exception to this is the Inuit, who live in a place with little sunlight, but have dark skin because they eat a lot of fish and have enough vitamin D.
Evolution has given us a rainbow of skin colors. Humans have always had melanin to determine our skin color. What has changed through history is the environment where we have lived. This has in turn changed our melanin production, and eventually, skin color.
| Brief 1 | People living in a particular 2usually have the same skin color and there are many different skin colors in the world. |
| Reason for skin color | The reasons for different skin colors mainly3in biology and history. |
| Biology reasons | The amount of melanin, by which a person’s skin color is __4 , varies from people to people. The more melanin a person has, the __5 his or her skin will be. Vitamin D is another source6 skin color. Vitamin D is necessary for humans to build bones. Sunlight contributes to vitamin D in the skin. |
| Historical reasons | The earliest people in Africa hioknj006Dad dark skin with hair covering it because the sunlight is very strong. When they moved to places where they could not get enough sunlight to __7___ vitamin D, their skin color became lighter. Generally speaking, people in areas with strong sunlight, have darker skin ____8people in other areas have lighter skin. |
| 9 | Melanin 10 an important role in our skin color. With our living environment changing, melanin production is changed, which leads to the changes in our skin color. |
高二英语阅读理解中等难度题查看答案及解析
The jobs of the future have not yet been invented. 1. . By helping them develop classic skills that will serve them well no matter what the future holds.
1. Curiosity
Your children need to be deeply curious. 2. . Ask kids, “What ingredients (配料) can we add to make these pancakes even better next time?” and then try them out. Ingredients make the pancakes better? What could we try next time?
2. Creativity
True creativity is the ability to take something existing and create something new. 3. . There are a dozen different things you can do with them. Experimenting with materials to create something new can go a long way in helping them develop their creativity.
3.Personal skills
Understanding how others feel can be a challenge for kids. We know what’s going on inside our own head, but what about others? Being able to read people helps kid from misreading a situation and jumping to false conclusions. 4. . “Why do you think she’s crying?” “Can you tell how that man is feeling by looking at his face?” “If someone were to do that to you, how would you feel?”
4. Self Expression
5. there are many ways to express thoughts and ideas-music, acting, drawing, building, photography. You may find that your child is attracted by one more than another.
A. Encourage kids to cook with you.
B. And we can’t forget science education.
C. We can give kids chances to think about materials in new ways.
D. So how can we help our kids prepare for jobs that don’t yet exist?
E. Gardening is another great activity for helping kids develop this skill.
F. We can do this in real life or ask questions about characters in stories.
G. Being able to communicate ideas in a meaningful way is a valuable skill.
高二英语信息匹配中等难度题查看答案及解析
The jobs of the future have not yet been invented.1.. By helping them develop classic skills that will serve them well no matter what the future holds.
Curiosity
Your children need to be deeply curious.2.. Ask kids, “What ingredients (配料)can we add to make these pancakes even better next time ?” and then try them out. Ingredients make the pancakes better? What could we try next time?
Creativity
True creativity is the ability to take something existing and create something new3.. There are a dozen different things you can do with them. Experimenting with materials to create something new can go a long way in helping them develop their creativity.
Personal skills
Understanding how others feel can be a challenge for kids. We know what’s going on inside our own head, but what about others? Being able to read people helps kid from misreading a situation and jumping to false conclusions.4.. “Why do you think she’s crying?” “Can you tell how that man is feeling by looking at his face?” “If someone were to do that to you, how would you feel?”
Self Expression
5.there are many ways to express thoughts and ideas –music, acting, drawing, building, photography. You may find that your child is attracted by one more than another.
A. So how can we help our kids prepare for jobs that don’t yet exist?
B. And we can’t forget science education.
C. Being able to communicate ideas in a meaningful way is a valuable skill.
D. Encourage kids to cook with you.
E. Gardening is another great activity for helping kids develop this skill.
F. We can do this in real life or ask questions about characters in stories.
G. We can give kids chances to think about materials in new ways.
高二英语七选五中等难度题查看答案及解析
七选五
The jobs of the future have not yet been invented. 1. By helping them develop classic skills that will serve them well no matter what the future holds.
I. Curiosity
Your children need to be deeply curious. 2. Ask kids, “What ingredients (配料)can we add to make these pancakes even better next time?” and then try them out. Did those ingredients make the pancakes better? What could we try next time?
II. Creativity
True creativity is the ability to take something existing and create something new from it. 3. There are a dozen different things you can do with them. Experimenting with materials to create something new can go a long way in helping them develop their creativity.
III. Personal skills
Understanding how others feel can be a challenge for kids. We know what’s going on inside our own head, but what about others? Being able to read people helps kid from misreading a situation and jumping to false conclusions. 4. “Why do you think she’s crying?” “Can you tell how that man is feeling by looking at his face?” “If someone were to do that to you, how would you feel?”
VI. Self Expression
5. There are many ways to express thoughts and ideas ---- music, acting, drawing, building, photography. You may find that your child is attracted by one more than another.
A. Encourage kids to cook with you.
B. And we can’t forget science education.
C. We can give kids chances to think about materials in new ways.
D. We can do this in real life or ask questions about characters in stories.
E. Gardening is another great activity for helping kids develop this skill.
F. So how can we help our kids prepare for jobs that don’t yet exist?
G. Being able to communicate ideas in a meaningful way is a valuable skill.
高二英语七选五中等难度题查看答案及解析
Have you ever wondered why certain people always say they are lucky? Some people say the secret of being born lucky is probably a summer birthday. May babies are the most likely to enjoy a lifetime of good fortune, a study of 40,000 people has found. The time of year you are born has a lasting influence on optimism and whether people think they are lucky, British and Swedish scientists said. May is the luckiest month to be born in, with half of those born then considering themselves lucky. October is the least lucky month with only 43 percent claiming good fortune.
The study adds to evidence that luck is not all down to chance, but is also affected by a person’s attitude. Another research has shown that whether people think themselves lucky depends more on having a “glass half-full” (instead of “half-empty”) approach to life, than on success. Professor Richard Wiseman, who led the study, said, “Something is influencing how people feel about their luck. People create their own luck through their attitude towards life.”
Luck is a mental state and not a matter of blind chance. There could be two reasons why those born in spring and summer reported themselves luckier than those born in autumn or winter. “One theory is that the temperature at the time of birth might be helpful to the development of the brain.” He said. “People born in winter are more likely to suffer from depression”. He said another possible reason is that mothers may be in a bad mood during winter, which influences their babies. The researchers said their findings were based on statistics only, and would not be true for everyone.
What’s depression? Medical depression is when one feels so sad and hopeless that sometimes he can’t imagine being happy. The pain becomes so deep that you don’t feel like participating in life. People who are permanently depressed usually have physical problems like stomachaches, headaches, and lack of energy. As you probably know, some people experience such deep depression that they believe suicide (killing yourself) is the only way to escape their pain.
1.Why can your birthday influence your attitude towards life?
A. The time of your birthday determines how fortunate you will be.
B. Mothers may feel differently in different seasons, and their moods influence their babies.
C. How successful you will be lies in the hour of your birthday.
D. How you feel about your health is influenced by the time of your birthday.
2.Having a “half-full” approach to life is a (an) ______ attitude.
A. optimistic B. pessimistic C. lucky D. depressing
3.Which of the following is NOT true according to the passage?
A. People born in summer are probably more optimistic than those born in winter.
B. A person’s luck may be affected by his attitude.
C. Depression may harm one’s physical health.
D. Luck is never a matter of chance.
4.According to the research result, one’s luck mainly depends on ______.
A. chance B. the month to be born in
C. one’s attitude to life D. health state
高二英语阅读理解中等难度题查看答案及解析
Have you ever wondered why successful people are so successful? Habits play an essential role in shaping our lives. We all know that bad habits can be harmful to your mental and physical well-being. 1. Good habits, on the other hand, can help you rise above others and be at your best. So, what are the common habits of successful persons that set them apart from the rest of us?
2. Most successful figures spend half an hour or more on newspapers, magazines and other books on a daily basis. Most of them have a preference for non-fiction piece that include history, self-help books, and biographies.
Getting up early. The majority of successful people rise approximately 3 hours before their actual workday starts. It gives them adequate time to get additional things done, which may include completing side projects, working out, or just planning ahead. 3.
Working out and staying in shape. We all know the benefits of a healthy lifestyle especially working out and staying physically fit. 4. Clearing your mind and challenging yourself physically with a tough workout daily helps you stay ready for the daily challenges of a business. To sum it up, a strong body carries a strong mind.
Working on communication skills. Communication plays a key role in building constructive interpersonal relationships on a personal as well as on a professional level. 5. However, if you are unable to convey the right information and message in a timely manner, you are less likely to achieve your goals. As with other skills, it is vital to continuously work on improving communication to help you stay more efficient while communicating with anyone on any level.
A. Applying technology.
B. Keeping reading as a habit.
C. After all, the early bird catches the worm.
D. Developing a healthy lifestyle is demanding.
E. Working with data, facts, and figures is important.
F. Successful people require mental and physical fitness.
G. They can block your road to achievement and success.
高二英语七选五困难题查看答案及解析
People often have this belief ______ development is bad for the environment, but this does not have to be true.
| A．that | B．which | C．where | D．how |
高二英语单项填空简单题查看答案及解析
People often have this belief ___development is bad for the environment, but this does not have to be true.
A which B whose C that D when
高二英语简单题查看答案及解析