Hummingbirds(蜂鸟) are one of nature’s most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.
Now scientists have found that it is the ratio(比值) of the bird’s wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.
David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink’s team used the same machine to test the blades from an advanced micro-helicopter used by the UK’s army. They found that the micro-helicopter’s blades are as efficient at hovering as the average hummingbirds.
But while the micro-helicopter’s blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird’s wing. The wings of Anna’s hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter’s blades.
While Professor Lentink wasn’t surprised at nature’s superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it’s amazing that we’re getting closer. It’s not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”
Professor Lentink said that we don’t know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.
1.What did the scientists find about hummingbirds?
A. Their wings are long and wide
B. They can hover in the air for a long time
C. The ratio of their wing length to wing width is very important
D. They are the most energetic flier in nature
2.Which is the right order of Professor Lentink’s research?
①Tested wings from different species of hummingbirds
②Got resources from museums
③Analyzed the results and drew a conclusion
④Tested the blades from a micro-helicopter
A. ①②③④ B. ②①③④
C. ②④①③ D. ②①④③
3.According to Professor Lentink, what will be the focus of future experiments?
A. To know how hummingbirds can fly in a strong wind
B. To know how hummingbirds change direction so quickly
C. To develop a new kind of helicopter
D. To study the secrets of hummingbirds
高三英语阅读理解困难题
Hummingbirds(蜂鸟) are one of nature’s most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.
Now scientists have found that it is the ratio(比值) of the bird’s wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.
David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink’s team used the same machine to test the blades from an advanced micro-helicopter used by the UK’s army. They found that the micro-helicopter’s blades are as efficient at hovering as the average hummingbirds.
But while the micro-helicopter’s blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird’s wing. The wings of Anna’s hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter’s blades.
While Professor Lentink wasn’t surprised at nature’s superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it’s amazing that we’re getting closer. It’s not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”
Professor Lentink said that we don’t know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.
1.What did the scientists find about hummingbirds?
A. Their wings are long and wide
B. They can hover in the air for a long time
C. The ratio of their wing length to wing width is very important
D. They are the most energetic flier in nature
2.Which is the right order of Professor Lentink’s research?
①Tested wings from different species of hummingbirds
②Got resources from museums
③Analyzed the results and drew a conclusion
④Tested the blades from a micro-helicopter
A. ①②③④ B. ②①③④
C. ②④①③ D. ②①④③
3.According to Professor Lentink, what will be the focus of future experiments?
A. To know how hummingbirds can fly in a strong wind
B. To know how hummingbirds change direction so quickly
C. To develop a new kind of helicopter
D. To study the secrets of hummingbirds
高三英语阅读理解困难题查看答案及解析
Rivers are one of our most important natural resources. Many of the world’s great cities are located on rivers, and almost __1_______ country has at least one river __2_______(flow) through it that plays __3________ important part in the lives of its people.
Since the beginning of history, people _4______________ (use) rivers for transportation. The longest one in the United States is the Mississippi, and the lifeline of Egypt is the Nile. __5_____________ transportation, rivers give water to drink, water for crops, and chances for fun and recreation (消遣,娱乐活动)for the people __6________________ live along their banks.
However, large cities and industries that are located on rivers often make problems. As the cities grow __7____________ size and industries increase in number, the water in the rivers becomes __8_____________ (pollute) with chemicals and other materials. People come to kwon the __9_____________ (important) of doing more to keep their rivers clean __10_____________ they want to enjoy the benefits of this natural resource.
高三英语填空题简单题查看答案及解析
阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式
Rivers are one of our most important natural resources. Many of the world’s great cities are located on rivers and almost every country has at least one river 1. (flow) through it, which plays an important part in the lives of 2. (it) people.
Since the beginning of history, people 3. (use) rivers for transportation. The Yellow River and Changliang River play a large role in China. The Mississippi, the 4. (long) one in the United States ever influenced the American people 5. (great) in history. The lifeline of Egypt is the Nile. Rivers provide fresh water 6. drink, grow crops, make electricity and chances to have fun for those 7. live along their banks.
8. the cities grow in size and industries increase in number, the river water is severely being polluted. It urges all countries to make 9. (decide) and take immediate action to stop it from 10. (pollute) any more.
高三英语语法填空困难题查看答案及解析
This story took place when I was about 12 years old.
Hummingbirds(蜂鸟)are small birds only about 3 inches long.Each spring they migrate to America from Mexico and Central America.They spend summer here and then fly the 2,000 miles back in the fall.
My Dad had just picked me up from school on one of the first cool days of fall.On our way home I saw a Hummingbird lying dead on the sidewalk.It had flown into the large plate glass and broke its neck.I picked up the tiny bird.I decided to take it home for burial.It seemed a shame for such a beautiful bird to be crushed by passers-by.
Little did I know that Hummingbirds can go into a state of hibernation(冬眠)daring cold temperatures.While like this they might appear to be dead.As soon as the bird warms up,all of its functions will return to normal.
About half way home I started to feel a small movement in my hands.I was quite startled.Evidently the hummingbird was NOT dead.The warmth from my hands was reviving(使恢复)the bird.When we got home Dad opened door for me and I stepped out of the car.I slowly and cautiously opened my hand.The hummingbird flew away to a nearby cornfield and wets thrilled to be on his way south again.
One of the most amazing things about hummingbird migration is that,after such a long journey,so many of them find their way back to me exact same location every spring.So maybe he was one of the hummingbirds I saw again the next year sipping nectar(花蜜)from the feeder hanging on our back porch.
1.Where do hummingbirds spend their summer?
A. In North America. B. In Central America.
C. In Mexico. D. In South America.
2.What happened to the hummingbird the author picked up on his way home?
A. It was almost frozen to death.
B. It was killed bumping into the window.
C. It was hurt and then fell into hibernation.
D. It was lost on its way of migration.
3.How did the author feel when he felt the bird move in his hand?
A. Surprised. B. Please.
C. Terrified. D. Puzzled.
4.The author's purpose in writing the passage is to tell us______.
A. some knowledge about hummingbirds
B. his experience in saving a hummingbird
C. to protect wildlife as much as we can
D. hummingbirds can remember the person who save them
高三英语阅读理解中等难度题查看答案及解析
Modern women are energetic, ambitious, and most of all, persistent_________ their goals.
A.in pursuit of B.in return for C.in touch with D.in contrast to
高三英语单项填空中等难度题查看答案及解析
The most energetic and important festivals are ________ that look forward to the end of winter and the coming of spring.
A. the ones B. others C. / D. ones
高三英语单项填空中等难度题查看答案及解析
Queensland is one of the most amazing states in Australia. It has some of the most beautiful natural scenery on the planet, with the Great Barrier Reef, rainforests and impressive beaches.
The Great Barrier Reef
It is one of the world’s largest natural features. It stretches more that 2,300 km along the north eastern coast of Australia from the northern tip of Queensland to just north of Bundaberg. The things that most surprise visitors to the reef are the colors.
Without doubt, the best way to see the Great Barrier Reef is by diving. If you have a little extra money and you are feeling a bit lazy, you can fly over the reef in a plane.
Fraser Island
Another area of natural beauty is Fraser Island. This is the world’s largest sand island. It’s best visited from Hervey Bay on the mainland, where there are a number of places offering trips around the island. To fully appreciate Fraser Island you should go for three or four days. Attractions include some beautiful fresh-water lakes, particularly Lake Wabby and Lake Mckenzie. You can walk around these on white sands untouched by human footprints. Indian Head also has some beautiful views. Braver travelers can go and watch sharks circling the water hundreds of meters below.
The Whitsunday Islands
It would be a pity to travel around Queensland without taking a trip around the Whitsunday Islands. They were named by Captain Cook in 1770, after the day on which he arrived. Here are some of the great things you can do there.
●Cruise around them on a relaxing trip.
●Take a sailing course.
●Look at the aboriginal (土著的) paintings in caves on Hook Island.
●Have fun in the water doing lots of water sports.
So, will you be going to Queensland?
1.The best way to admire the beauty of the Great Barrier Reef is .
A. diving in the sea
B. taking a boat
C. flying in a plane
D. driving
2.What can we infer from Fraser Island?
A. Few places on the mainland can offer trips around the island.
B. One should have at least 2 days to fully explore Fraser Island.
C. Lake Wabby and Lake Mckenzie are rarely visited places.
D. Only brave ones can watch sharks in the deep ocean.
3.If you want to learn sailing, you can go to .
A. Hook Island
B. The Whitsunday Islands
C. Fraser Island
D. the Great Barrier Reef
4.The purpose of writing this passage is .
A. to adverse for Queensland
B. to inform the latest news
C. to call on people to protect Queensland
D. to break a world record
高三英语阅读理解简单题查看答案及解析
Queensland is one of the most amazing states in Australia. It has some of the most beautiful natural scenery on the planet, with the Great Barrier Reef, rainforests and impressive beaches.
The Great Barrier Reef
It is one of the world’s largest natural features. It stretches more than 2,300 km along the north eastern coast of Australia from the northern tip of Queensland to just north of Bundaberg. The things that most surprise visitors to the reef are the colors.
Without doubt, the best way to see the Great Barrier Reef is by diving. If you have a little extra money and you are feeling a bit lazy, you can fly over the reef in a plane.
Fraser Island
Another area of natural beauty is Fraser Island. This is the world’s largest sand island. It’s best visited from Hervey Bay on the mainland, where there are a number of places offering trips around the island. To fully appreciate Fraser Island you should go for three or four days. Attractions include some beautiful fresh-water lakes, particularly Lake Wabby and Lake Mckenzie. You can walk around these on white sands untouched by human footprints. Indian Head also has some beautiful views. Braver travelers can go and watch sharks circling the water hundreds of meters below.
The Whitsunday Islands
It would be a pity to travel around Queensland without taking a trip around the Whitsunday Islands. They were named by Captain Cook in 1770, after the day on which he arrived. Here are some of the great things you can do there.
●Cruise around them on a relaxing trip.
●Take a sailing course.
●Look at the aboriginal (土著的) paintings in caves on Hook Island.
●Have fun in the water doing lots of water sports.
So, will you be going to Queensland?
1.The best way to admire the beauty of the Great Barrier Reef is ________________________________________________________________________________________________.
A. driving B. taking a boat
C. flying in a plane D. diving in the sea
2.What can we infer from Fraser Island?
A. Lake Wabby and Lake Mckenzie are rarely visited places.
B. Only brave ones can watch sharks in the deep ocean.
C. Few places on the mainland can offer trips around the island.
D. One should have at least 2 days to fully explore Fraser Island.
3.If you want to learn sailing, you can go to ________________________________________________________________________________________.
A. Hook Island B. The Whitsunday Islands
C. Fraser Island D. the Great Barrier Reef
4.The purpose of writing this passage is ________________________________________________________________________________.
A. to call on people to protect Queensland B. to inform the latest news
C. to adverse for Queensland D. to break a world record
高三英语阅读理解简单题查看答案及解析
Bamboo (竹子) is one of nature’s (自然) most surprising plants. Many people call this plant a tree, but it is a kind of grass.
Like other kinds of grass, a bamboo plant may be cut very low to the ground, but it will grow back very quickly. A Japanese scientist reported one bamboo plant which grew 1.5 metres (4 feet) in 24 hours! Bamboo grows almost everywhere in the world except Europe. There are more than 1, 000 kinds of bamboo.
Not all bamboo looks the same. Some bamboo plants are very thin. They may only grow to be a few centimeters wide while others may grow to more than 30 centimetres (1 foot) across. This plant also comes in different colors, from yellow to black to green.
Bamboo has been used to make many things such as hats and kitchen tools. Because it is strong, bamboo is also used to build buildings.
Many Asian countries have used bamboo for hundreds of years. They often use bamboo for buildings and supporting new buildings and bridges while they are being built.
In Africa, poor farmers are taught how to find water using bamboo. These African countries need cheap way to find water because they have no money, and their crops often die from no rain and no water. Bamboo pipes help poor farmers bring water to their thirsty fields without spending a lot of money.
1.How is bamboo like grass?
A. It grows quickly. B. It’s wood.
C. It is easy to cut D. It is very thin
2.Though you can see bamboo everywhere, it doesn’t grow ______.
A. in China B. in Europe
C. on mountains D. in Africa
3.Why is bamboo used by African poor farmers?
A. Because it is cheap.
B. Because it has different colours .
C. Because it is strong.
D. Because it has been used by Asians.
4.Bamboo pipes can ______.
A. make money B. be trees
C. grow quickly D. carry water
高三英语阅读理解中等难度题查看答案及解析
While most people consider that laughter is one of the nature’s great treatments for a whole range of mental and physical diseases, it is still a serious scientific subject that researchers are trying to figure out.
“Laughter is social.” says Robert R. Provine, author of the book “Laughter: A Scientific Investigation”, who has been studying laughter for decades. “Almost all people laugh ‘ha-ha-ha’ basically the same way. Whether you speak Mandarin, French or English, everyone will understand laughter. There is a pattern generator(发生器) in our brain that produces this sound.
Laughing is also a good way of communicating. Babies laugh long before they speak. No one teaches them how to laugh. They just do it. People may laugh at a prank(恶作剧) on April Fools’ day. But surprisingly, only 10 to 15 percent of laughter is the result of someone making a joke. Laughter is mostly about social responses rather than reaction to a joke. Deaf people laugh without hearing and people on cell phones laugh without seeing, which shows that laughter isn’t dependent on a single sense but on social interactions.
And laughter is not just a human thing. Chimps tickle(挠痒) each other and even laugh when another chimp pretends to tickle them.
Jaak Panksepp studies rats that laugh when he tickles them. It turns out rats love to be tickled. They return again and again to the hands of researchers tickling them, Panksepp’s video shows.
By studying rats, scientists can figure out what’s going on in the brain during laughter. It has been found that laughter in rats produces a chemical that acts as an antidepressant(抗抑郁药) and anxiety-reducer. Scientists think the same thing probably happens in humans, too. This would give doctors a new chemical target in the brain in their effort to develop drugs that fight depression and anxiety in people.
Even so, laughter itself has not been proved to be the best medicine, experts said. “No study has shown that laughter produces a direct health benefit,” Provine said, “largely because it’s hard to separate laughter from just feeling good.”
1. Why does the writer say “laughter is mostly about social responses rather than reaction to a joke”?
A. because people can communicate with each other by laughing.
B. because laughter is the same sound in all the human’s languages.
C. because laughter is considered a basic language all people can learn.
D. because everyone can understand the meaning of the word laughter.
2.From the last two paragraphs we know that______.
A. laughter has no direct connection with good feelings
B. laughing every day can cure people of many diseases
C. the medical functions of laughter are still under experiment
D. scientists have learned what is happening in a human brain when he laughs
3. Which of the following statements is true according to the passage?
A. Laughter depends on many senses.
B. Laughter is a social response shared by all creatures.
C. If you speak different languages, you will laugh differently.
D. A new medicine has been developed based on the laughter research.
高三英语阅读理解中等难度题查看答案及解析