A group of scientists trained dogs to detect(发现)a crop disease called citrus greening. The disease has affected orange, lemon and grapefruit trees in the American states of Florida, California and Texas. The dogs can detect the disease weeks to years before it appears on tree leaves and roots, the researchers report. Using dogs is also faster, less costly and more exact than having people collect hundreds of leaves for lab analysis.
Timothy Gottwald is a researcher in the study. He said, “This technology is thousands of years old — the dog's nose. We’ve just trained dogs to hunt new prey：the bacteria that cause a very damaging crop disease.”
Citrus greening is caused by a kind of bacteria that are spread by a tiny insect that feeds on the leaves and stems of citrus trees. Once a tree is infected(感染)，there is' no cure. The disease has also hurt citrus crops in Central and South America and Asia. In one experiment involving grapefruit trees in Texas, trained dogs were correct 95 percent of the time in telling the difference between newly infected trees and healthy ones. “The earlier you detect the disease, the better chance you have at stopping healthy trees being infected by removing infected ones,” Gottwald said.
Professor Matteo Garbelotto says the new research shows that dogs can detect an infection well before present methods. He has been involved in similar research but had no part in the new study.
Laura Sims is a plant scientist. She praised the steps taken to find out if the dogs were detecting the bacteria itself or a plant's reaction to an infection. To do that, the researchers infected different kinds of unrelated plants with the bacteria in a laboratory. The dogs were still able to pick out the infected plants.
Gottwald said, "You've seen dogs working in airports, detecting drugs and explosives. Maybe soon you will see them working on more farms."
1.What does the text say about citrus greening?
A.It mainly damages tree branches.
B.It' s impossible to detect at an early stage.
C.Dogs can better detect it than humans.
D.Humans have to analyze tree roots to detect it.
2.How does a dog detect citrus greening?
A.By tasting. B.By touching.
C.By observing. D.By Sniffing.
3.Early detection of citrus greening enables farmers to ______.
A.help infected trees to recover B.keep it from spreading further
C.improve the quality of fruit. D.better protect infected trees
4.Which of the following statements reflects Gottwald's opinion?
A.Dogs will take the place of humans to conduct risky jobs.
B.Trained dogs make no mistakes in citrus greening detection.
C.Dogs use plants' reaction to an infection to help with their detection.
D.Using dogs for citrus greening detection will be more widespread.
高三英语阅读理解中等难度题
A group of scientists trained dogs to detect(发现)a crop disease called citrus greening. The disease has affected orange, lemon and grapefruit trees in the American states of Florida, California and Texas. The dogs can detect the disease weeks to years before it appears on tree leaves and roots, the researchers report. Using dogs is also faster, less costly and more exact than having people collect hundreds of leaves for lab analysis.
Timothy Gottwald is a researcher in the study. He said, “This technology is thousands of years old — the dog's nose. We’ve just trained dogs to hunt new prey：the bacteria that cause a very damaging crop disease.”
Citrus greening is caused by a kind of bacteria that are spread by a tiny insect that feeds on the leaves and stems of citrus trees. Once a tree is infected(感染)，there is' no cure. The disease has also hurt citrus crops in Central and South America and Asia. In one experiment involving grapefruit trees in Texas, trained dogs were correct 95 percent of the time in telling the difference between newly infected trees and healthy ones. “The earlier you detect the disease, the better chance you have at stopping healthy trees being infected by removing infected ones,” Gottwald said.
Professor Matteo Garbelotto says the new research shows that dogs can detect an infection well before present methods. He has been involved in similar research but had no part in the new study.
Laura Sims is a plant scientist. She praised the steps taken to find out if the dogs were detecting the bacteria itself or a plant's reaction to an infection. To do that, the researchers infected different kinds of unrelated plants with the bacteria in a laboratory. The dogs were still able to pick out the infected plants.
Gottwald said, "You've seen dogs working in airports, detecting drugs and explosives. Maybe soon you will see them working on more farms."
1.What does the text say about citrus greening?
A.It mainly damages tree branches.
B.It' s impossible to detect at an early stage.
C.Dogs can better detect it than humans.
D.Humans have to analyze tree roots to detect it.
2.How does a dog detect citrus greening?
A.By tasting. B.By touching.
C.By observing. D.By Sniffing.
3.Early detection of citrus greening enables farmers to ______.
A.help infected trees to recover B.keep it from spreading further
C.improve the quality of fruit. D.better protect infected trees
4.Which of the following statements reflects Gottwald's opinion?
A.Dogs will take the place of humans to conduct risky jobs.
B.Trained dogs make no mistakes in citrus greening detection.
C.Dogs use plants' reaction to an infection to help with their detection.
D.Using dogs for citrus greening detection will be more widespread.
高三英语阅读理解中等难度题查看答案及解析
Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world’s freshwater withdrawals from rivers, lakes and other water resources go toward irrigating fields.
Scientists are using biotechnology as well as traditional breeding methods to develop water-saving crops to feed a growing world.
Thomas “Tommy” Carter is a plant scientist in North Carolina. He works for the Agricultural Research Service in the United States Department of Agriculture. He leads Team Drought, a group of researchers at five universities. They have been using conventional breeding methods to develop and test soybeans that can grow well under dry conditions.
Tommy Carter started working on drought-resistant soybeans in 1981. His research has taken him as far as China, where soybeans have been grown for thousands of years.
Farmers in the United States, however, have grown soybeans for only about a century. Tommy Carter says the soybeans they grow are for the most part genetically similar. More differences could better protect crops against climate changes that can reduce production. Those changes include water shortages which could increase from global warming.
The Agriculture Department has a soybean germplasm(胚质) collection, a collection of genetic material passed from one generation to the next. Members of Team Drought studied more than 2,500 examples from the collection.
They looked at ones from the home of soybeans, Asia. They searched for germplasms that could keep plants from weakening and wilting (凋谢)during hot, dry summers in the United States.
Tommy Carter says they found only five. But these slow-wilting lines, he says, produce four to eight bushels（英斗）more than normal soybeans under drought conditions. The yield depends on location and environment.
Scientists are also working on other plants that either use less water or use it better, or both. For example, companies like Monsanto, DuPont and Syngenta have been developing corn with reduced water needs. Monsanto expects to be ready in a few years to market its first corn seeds genetically engineered to resist drought.
1.According to the passage, scientists try to find out how to _______.
A. grow crops with less water
B. increase crop production
C. feed a growing world
D. save the world’s water resource
2.Why did Tommy Carter come to China?
A. He likes traveling.
B. China has a long history.
C. He’s doing research into soybeans.
D. He works for the Agricultural Research Service.
3.What’s inferred from the passage?
A. Climate changes lead to global warming.
B. Water shortages contribute to global warming.
C. Genetically different soybeans need much water to grow.
D. Genetically different soybeans help to fight against damaging climate changes.
4.What do we know about slow-wilting plants talked about in the passage?
A. They yield big profits.
B. They can grow in almost any climate.
C. They seem to be drought-resistant.
D. They need much water for their growth.
高三英语阅读理解中等难度题查看答案及解析
Now _____ understanding of climate change is no longer limited to ____ small group of scientists or environmentalists.
A. / ; a B. an ; a C. the ; the D. a ; /
高三英语单项填空中等难度题查看答案及解析
A global group of scientists have reduced the time it takes to find and introduce disease-resistance genes from wild plants into domestic crops such as rice, wheat and potato, a research revealed on Tuesday.
Scientists from the John Innes Center in Britain, along with colleagues from Australia and the United States, have created a database known as AgRenSeq, where researchers can easily search for resistance genes already discovered in wild relatives of modern crops.
The study was co-authored by a global expert Professor HarbansBariana from the University of Sydney, who said that this technology will support the discovery and characterization of new sources of disease resistance in plants. Once researchers have identified resistance genes using AgRenSeq, they can clone them and introduce them to domestic crops to protect against diseases and pests,
“We have found a way to scan the genome(基因组)of a wild relative of a crop plant and pick out the resistance genes we need and we can do it in record time,” Dr. Brande Wulff, a project leader from the John Innes Centre, said.
“This used to be a process that took l0 Or 15 years and was like searching for a needle in a haystack(干草堆),” Wulff said. “We have perfected the method so that we can clone these genes in a matter of months and for just thousands of dollars instead of millions.”
The team are highly optimistic about their work, predicting it to be utilized in protecting many crops with wild relatives including soybeans, pea, cotton, potato, wheat, rice, banana and cocoa. “Using speed cloning and speed breeding we could deliver resistance genes into the best varieties within a couple of years, like a phoenix(凤凰) rising from the ashes,” Wulff added.
1.How have the researchers developed the resistance genes?
A.By reducing the research time.
B.By introducing them to wild plants.
C.By cloning them from domestic crops.
D.By getting resistance genes from wild plants.
2.What will be the use of the study in the future?
A.It will protect crops from being damaged by pests.
B.It will create a database for researchers to search.
C.It will protect domestic crops for 10 to 15 years.
D.It will contribute to reducing the wild plants.
3.Which of the following best explains “utilized” underlined in Paragraph 6?
A.Produced. B.Made.
C.Used. D.Studied.
4.What can we infer from what Brande Wulff said?
A.The resistance genes cost millions of dollars.
B.The resistance genes were found in a haystack.
C.It took the researchers ten years to find the resistance genes.
D.Disease-resistance genes will be put into practice soon.
高三英语阅读理解中等难度题查看答案及解析
Recently, a group of scientists decided to find out what the funniest joke in the world was. This was obviously a difficult task, as no two people really agree about what is funny and what is not—especially when they are from different countries.
Here is the joke which the experts decided was the funniest joke in the world：
Two hunters were out in the woods. One of them fell to the ground. He didn’t seem to be breathing; his eyes were closed. The other hunter took out his mobile phone and called the emergency services.
“My friend is dead!” he cried to the operator. “What can I do？”The operator said，“Don’t worry. First, make sure he’s dead.” There was a silence, and then a shot was heard. Bang! The hunter’s voice came back on the line. He said, “OK, now what?”
This is perhaps amusing. Culturally, it depends on us knowing that often hunters are not considered to be very intelligent people, and that often they are quite violent. But perhaps this is not so all over the world. It’s also quite a “black” joke—a joke about something which isn’t really a funny subject. The experts also found the second funniest joke in the world. Here it is：
Sherlock Holmes and Dr. Watson went on a camping trip. After dinner, they went to sleep. Some hours later, Holmes woke up. “Watson, look up at the sky and tell me what you see.” “I see millions of stars, Holmes,” replied Watson.
“And what do you infer from that? ”
“Well, there are billions of stars ... we are a small part of the universe ...”
“Watson, you idiot!” he said. “Someone has stolen our tent!” I personally think this is better.
Can scientists in the end decide what is funny? Some things are much too complicated, even for scientists.
1.What can we learn from the first paragraph?
A.Few jokes can make scientists laugh.
B.Only scientists can find out the funniest joke.
C.There are different jokes in different countries.
D.People hold different opinions about what is funny.
2.What does the author think of the first joke?
A.It is not so funny as the experts thought.
B.It is really the funniest joke he has ever heard.
C.It can greatly affect readers’ attitudes toward hunters.
D.It shows that not all hunters are brave and intelligent.
3.We can learn that a person’s understanding of a joke can be affected by ________.
A.the reader’s feeling B.the length of the joke
C.the reader’s cultural background D.the language that the teller uses
4.Which of the following is the best title for this passage?
A.Uninteresting jokes B.Different kinds of jokes
C.The funniest jokes in the world D.Tips on how to make others laugh
高三英语阅读理解中等难度题查看答案及解析
Dogs are known for a strong sense of smell. Their noses can be trained to identify different smells. Dogs are often used in search and rescue operations and to sniff for things like drugs and explosives. Some dogs have even been trained to sniff for cancer in people.
Researchers have been trying to reproduce the extraordinary sense of smell that real dogs are born with. Now, officials at the Glasgow airport in Scotland are testing a new security device called an “electronic sniffer dog”. The electronic sniffer dog represents one of the latest developments in the area of smell technology.
A Scottish company, Cascade Technologies, joined with the French security company Morpho to develop it. The device uses lasers to identify explosive materials in gases in the air. The purpose is to identify explosives that may be hidden on a person’s body.
The machine looks similar to the metal detectors now used at airports. Passengers walk through the machine as the lasers test the surrounding air. People are not required to take off their coats, belts or shoes as part of the security process. And, unlike full-body scanners, the new device does not show images of the passengers.
Officials at Cascade Technologies say the machine can process one person per second and produce almost immediate results. They say future development could cut security processing times at airports by screening all passengers at walking speed.
Professor Yushan Yan, the head of Chemical and Environmental Engineering at the University of California, Riverside, points out that unlike real dogs, electronic devices do not get tired or need to be walked or require food and water. Professor Yan says real dogs also have other needs. “They also need very extensive training that could be expensive. And when they work they have to have a very skilled handler around them.”
But Professor Yan says there is an important area where man’s best friend still wins compared to technology. “In terms of sensitivity and selectivity, the current technology out there is still inferior. The real dog has amazing capability of identifying some really minor amount of explosives.”
1. The electronic sniffer dogs will be used to____
A. replace real dogs to be as pets for people
B. search for and rescue people who are in trouble
C. help people look after patients in the hospital
D. identify drugs and explosives in places like the airport
2.Which of the following is true of the electronic sniffer dog?
A. The device uses lasers to examine for explosive materials.
B. People have to take off their clothes when walking through the device.
C. The device will show images of the passengers.
D. The device can process all passengers at walking speed.
3. The advantages of the electronic sniffer dog over the real dog include the following EXCEPT______
A. its convenience B. its high efficiency
C. its sensitivity D. its low consumption
4.The underlined word “inferior” in the last paragraph most probably has the meaning of_____.
A. concentrating all one’s effort on a specific area
B. not as good as sb. / sth. else
C. that cannot be clearly understood
D. necessary for completeness
高三英语阅读理解中等难度题查看答案及解析
Scientists around the world are striving for effective detection of cancer in the early stages,which is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body,and a Chinese scientist may have found a quick way of knowing whether malignant tumors（恶性肿瘤）exist in a patient's body,with just one drop of blood.
Malignant tumors in early phases can be cured.However,it's extremely difficult to be aware of cancer in its early stages,as patients don't show obvious symptoms and thus it can only be found in its later stages,which is already too late,so to detect cancer early remains a global challenge for scientists.
Back in 1989,scientists have found a kind of heat shock proteins (HSP),named Hsp90α,which existed in human bodies and can be used as a cancer biomarker detection kit.Scientists around the globe have been working on it since then,and more than 10,000 journals have been published on accredited magazines,yet no one has actually turned their research results into medical products.
However,Luo Yongzhang and his team in Tsinghua University's School of Life Sciences in Beijing seemed to have cracked the code,after working on the problem since 2009.The team has produced an artificial Hsp90α protein for clinical use that gains structural stability by regrouping proteins.The test kit can diagnose multiple kinds of cancer by analyzing a drop of human blood.This means they are able to "create" the protein,in any quantity,and at any time they wish to.
The kit has since been used in clinical trials involving 2,347 patients at eight hospitals in China.It was the first clinical trial in the world to test if the protein could be a useful tumor biomarker for lung cancer,and it succeeded. Now,the kit has been approved to enter the Chinese and European markets,24 years after Hsp90α was discovered.
1.Why is cancer hard to cure?
A. Malignant tumors are found too late.
B. Malignant tumors spread too quickly.
C. Its symptoms are shown in early stages.
D. No proper treatment can be applied to it.
2.What do we learn about Hsp90α from Paragraph 3?
A. It was created by scientists in 1989.
B. All magazines have covered the topic.
C. There has been a medical product about it.
D. It can serve as a cancer detection approach.
3.How does the Chinese kit diagnose cancer?
A. By regrouping proteins.
B. By cracking cancer’s code.
C. By breaking down one drop of blood.
D. By producing an artificial Hsp90α protein.
4.It can be inferred that a European with lung cancer in early phases .
A. can’t be cured in the end
B. can be diagnosed with it in time
C. has to be examined in China
D. expects the kit to come into the market
高三英语阅读理解中等难度题查看答案及解析
Detectives often look for footprints when they try to solve crimes. Scientists use footprints, too—dinosaur footprints when they try to figure out how dinosaurs lived and moved.
Dinosaurs died out about 65 million years ago. Today scientists work to solve the mysteries of these ancient animals.
Footprints, or tracks(脚印), are an important way to learn about dinosaurs. Christian Meyer of the Natural History Museum in Basel, Switzerland, calls dinosaur tracks “the closest thing to a movie” of dinosaurs.
“They tell us something about the size of the animal, the way they were walking…they tell us something about their speed,” Meyer said.
Tracks also show that dinosaurs sometimes traveled in groups. Traveling in groups probably helped dinosaurs protect themselves from enemies. Plus, some meat-eating dinosaurs may have hunted in groups, much like wolves do today. Being in a group could help dinosaurs work together to kill large animals.
Dinosaur footprints can be as small as a few inches across, but they can also be as big as a few feet across. Dinosaur footprints have been found throughout the world at over 1,500 sites, including a T. Rex footprint in New Mexico. “Trackways” are groups of footprints.
And scientists aren’t the only ones finding dinosaur tracks—kids can, too! Eleven-year-old Mark Turner and nine-year-old Daniel Helm discovered dinosaur tracks in British Columbia, anada. Soon scientists began studying the tracks.
Scientists and other people interested in studying dinosaurs are working to save the trackways from activities like construction and mining.
1.The passage mainly tells us that_______.
A. there were really dinosaurs on the earth millions of years ago
B. dinosaurs were the most frightening animals in the past
C. dinosaur footprints are important in learning about dinosaurs
C. why dinosaurs died out millions of years ago
2.By studying footprints scientists can know the following EXCEPT _______.
A. how big the dinosaur was B. what color the dinosaur was
C. how fast the dinosaur could run D. how the dinosaur walked
3. By working in groups, some meat-eating dinosaurs_______.
A. made the hunting of large animals easily
B. could travel a long way without being lost
C. could protect themselves from being hunted by wolves
D. could get to a place faster
4. From the last paragraph we can infer that some human activities like mining_______.
A. are helpful to the study of dinosaurs
B. can help scientists solve many mysteries
C. can lead to the discovery of the footprints
D. can destroy the footprints of the dinosaur
高三英语阅读理解简单题查看答案及解析
A policeman was questioning 3 blondes who were training to become detectives． To test their skills in recognizing a suspect, he shows the first blonde a picture for5 seconds and then hides it．
“This is your suspect, how would you recognize him?"
The first blonde answers, "That's easy, we'll catch him fast because he only has one eye!" The policeman says, "Well．．．uh．．．that's because the picture shows his profile．"
Slightly confused by this ridiculous response, he flashes the picture for 5 seconds at the second blonde and asks her, "This is your suspect, how would you recognize him?"
The second blonde giggles, flips her hair and says, "Ha! He'd be too easy to catch because he only has one ear!"
The policeman angrily responds, "What's the matter with you two? Of course only one eye and one ear are SHOWING because it's a picture of his profile!! Is that the best answer you can come up with?"
Extremely frustrated at this point, he shows the picture to the third blonde and in a very testy voice asks "This is your suspect, how would you recognize him?" He quickly adds, "Think hard before giving me a stupid answer．"
The blonde looks at the picture intently for a moment and says, "Hmmmm…the suspect wears contact lenses．"
The policeman is surprised and speechless because he really doesn't know himself if the suspect wears contacts or not． "Well, that's an interesting answer．．．wait here for a few minutes while I check his file and I’ll get back to you on that．" He leaves the room and goes to his office, checks the suspect's file in his computer, and comes back with a beaming smile on his face． "Wow! I can't believe it．．．it's TRUE! The suspect does in fact wear contact lenses． Good work! How were you able to make such an acute observation?"
"That's easy," the blonde replied． "He can't wear regular glasses because he only has one eye and one ear．"
1.Why did the policeman show a picture to the three blondes?
A． To inquire about their relationship with the suspect．
B． To test their potential of being detectives．
C． To train them as qualified police officers．
D． To show the skills in recognizing a suspect．
2.What's the policeman's attitude towards the first blonde's answer?
A． Angry． B． Puzzled．
C． Embarrassed． D． Satisfied．
3.What did the second blonde think of the task?
A． Demanding． B． Easy．
C． Ridiculous． D． Confusing．
4.How did the third blonde know that the suspect wore contact lenses?
A． By coincidence．
B． By random guess．
C． By logical and reasonable analysis．
D． By checking the file in the computer．
高三英语阅读理解中等难度题查看答案及解析
A policeman was questioning 3 blondes who were training to become detectives． To test their skills in recognizing a suspect, he shows the first blonde a picture for5 seconds and then hides it．
“This is your suspect, how would you recognize him?"
The first blonde answers, "That's easy, we'll catch him fast because he only has one eye!" The policeman says, "Well．．．uh．．．that's because the picture shows his profile．"
Slightly confused by this ridiculous response, he flashes the picture for 5 seconds at the second blonde and asks her, "This is your suspect, how would you recognize him?"
The second blonde giggles, flips her hair and says, "Ha! He'd be too easy to catch because he only has one ear!"
The policeman angrily responds, "What's the matter with you two? Of course only one eye and one ear are SHOWING because it's a picture of his profile!! Is that the best answer you can come up with?"
Extremely frustrated at this point, he shows the picture to the third blonde and in a very testy voice asks "This is your suspect, how would you recognize him?" He quickly adds, "Think hard before giving me a stupid answer．"
The blonde looks at the picture intently for a moment and says, "Hmmmm…the suspect wears contact lenses．"
The policeman is surprised and speechless because he really doesn't know himself if the suspect wears contacts or not． "Well, that's an interesting answer．．．wait here for a few minutes while I check his file and I’ll get back to you on that．" He leaves the room and goes to his ．office, checks the suspect's file in his computer, and comes back with a beaming smile on his face． "Wow! I can't believe it．．．it's TRUE! The suspect does in fact wear contact lenses． Good work! How were you able to make such an acute observation?"
"That's easy," the blonde replied． "He can't wear regular glasses because he only has one eye and one ear．"
1.Why did the policeman show a picture to the three blondes?
A．To inquire about their relationship with the suspect．
B．To test their potential of being detectives．
C．To train them as qualified police officers．
D．To show the skills in recognizing a suspect．
2.What's the policeman's attitude towards the first blonde's answer?
A．Angry． B．Puzzled． C．Embarrassed． D．Satisfied．
3.What did the second blonde think of the task?
A．Demanding． B．Easy． C．Ridiculous． D．Confusing．
4.How did the third blonde know that the suspect wore contact lenses?
A．By coincidence．
B．By random guess．
C．By logical and reasonable analysis．
D．By checking the file in the computer．
高三英语阅读理解中等难度题查看答案及解析