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Different Kinds of Birds
Avocets
There are 4 different species of Avocet found around the world-Pied Avocet , Red-necked Avocet, Andean Avocet, and American Avocet. This bird is found in North and South America, Europe, and even Australia. This long-legged bird has webbed feet and an upturned, thin bill.
Bald Eagles
The bald eagle is found in wetlands and near coastlines. They have very large and broad wings, with a broad tail. The head and tail are white in color, which is the major distinguishable factor of the bald eagle. The long, hooked bill is yellow in color. They feed on fish, ducks, rabbits, geese, etc.
Eastern Bluebirds
These are around 61／2 inches in length .Such birds are found mainly in gardens woodlands, and orchards with the arrival of spring. Male Eastern Bluebirds are bright blue on the upper half and have a white belly. Female Eastern Bluebirds have a grayish head with shades of blue as well. New York and Missouri have named this creature as their state bird.
Flamingos
These pink-bodied birds with a unique beak, are generally found in large groups. The beaks are capable of removing mud before they can eat their food. Flamingos can be found in many African countries, areas of Florida, and one particular type of species is found only in the Andean highlands.
Kingfishers
There are over 90 various species of Kingfishers found in the woodland areas as well as wetlands across the world. They are excellent divers when it comes to catching fish in the rivers. Their pointed bills are what help them bag the catch. Kingfishers have good eyesight whether they are in air or underwater.
1.____ most probably mean the same.
A. Bill and beak B. Head and beak C. Bill and belly D. Leg and feet
2.Which of the following is true?
A. Eastern Bluebirds are all blue in color.
B. Avocets can be found around the 
world.
C. The white head and tail make Bald Eagles distinguishable.
D. More Kingfishers can be found in wetlands than in the woodland areas.
3.Birds that can be found only in the Andean highlands are ________.
A. Bald Eagles
B. Female Eastern Bluebirds
C. Andean Avocets
D. one special type of Flamingos
4.It can be inferred from the passage that what Bald Eagles and Kingfishers have in common is their____.
A.habitats B. shapes C. ability to catch fish D. eyesight in air or under water
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When different species of birds flock (聚集) together, their flight formations are determined by social dynamics both between and within species.
New research from the Universities of Cambridge and Exeter reveals for the first time that, contrary to current models used to explain the movement of flocks, the differences between bird species and social relationships between individuals play a critical role in determining the dynamics of mixed-species flocks.
The unified(群集) behaviour of bird flocks has puzzled scientists for hundreds of years. One naturalist from the turn of the century even suggested telepathy(心灵感应)may be involved. There have since been more logical explanations, including mathematical models that show that repeated interactions among individuals following simple rules can generate coordinated (协同的)group movements. However, these models usually rely on the assumption that individuals within groups are identical and interact independently, which may not reflect reality.
Jolle Jolles, a PhD student at the University of Cambridge's Department of Zoology and author of the paper, said：“Spectacular collective behaviour can be found in a large range of animal species, and we now know that often these complex coordinated group movements may be the result of individuals following simple rules. However, rarely are the individual characteristics and social relationships within them taken into account. Our research highlights that these striking displays of group behaviour are much more complex.”
By analysing high-resolution photographs of mixed flocks of rooks and jackdaws (both from the corvid family), the researchers found that rather than individuals interacting in a consistent fashion throughout the flock, interactions depended on social dynamics between the different species as well as relationships within a species.
The researchers discovered that birds prefer to fly close to members of their own species, and that the larger and more dominant rooks take the lead by flying near the front of flocks. Additionally, the lifelong, monogamous(一妻一夫制的)pair bonds that are characteristic of both species seem to be reflected in flight, as birds often fly particularly close to a single, same-species partner.
Dr Alex Thornton, principal investigator of the Cambridge Jackdaw Project, now at the University of Exeter and author of the paper, said: “Together, our findings demonstrate that to understand the structure of groups — such as bird flocks — we need to consider the characteristics and relationships of the individuals within them.”
1.The underlined word “generate” means ______.
A. set down B. take away
C. bring about D. give up
2.According to Jolle Jolles, what are seldom considered about coordinated group movement?
A. Individual characteristics and social relationship between them
B. Repeated interactions among individuals and social dynamics
C. Telepathy and social relationship between them
D. The structure of groups and the varieties of species
3.Birds may prefer to fly the closest to _____ .
A. the largest one B. the most dynamic one
C. the lifelong partner D. the friendly partner
4.What is the main idea of the passage?
A. How birds interact in simple rules.
B. How birds of different feathers flock together.
C. Why birds show preference to flocking.
D. Why birds display the characteristics.
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How does an ecosystem(生态系统) work? What makes the populations of different species the way they are? Why are there so many flies and so few wolves? To find an answer, scientists have built mathematical models of food webs, noting who eats whom and how much each one eats.
With such models, scientists have found out some key principles operating in food webs. Most food webs, for instance, consist of many weak links rather than a few strong ones. When a predator(掠食动物) always eats huge numbers of a single prey(猎物), the two species are strongly linked; when a predator lives on various species, they are weakly linked. Food webs may be dominated by many weak links because that arrangement is more stable over the long term. If a predator can eat several species, it can survive the extinction(灭绝) of one of them. And if a predator can move on to another species that is easier to find when a prey species becomes rare, the switch allows the original prey to recover. The weak links may thus keep species from driving one another to extinction.
Mathematical models have also revealed that food webs may be unstable, where small changes of top predators can lead to big effects throughout entire ecosystems. In the 1960s, scientists proposed that predators at the top of a food web had a surprising amount of control over the size of populations of other species—including species they did not directly attack.
And unplanned human activities have proved the idea of top-down control by top predators to be true. In the ocean, we fished for top predators such as cod on an industrial scale, while on land, we killed off large predators such as wolves. These actions have greatly affected the ecological balance.
Scientists have built an early-warning system based on mathematical models. Ideally, the system would tell us when to adapt human activities that are pushing an ecosystem toward a breakdown or would even allow us to pull an ecosystem back from the borderline. Prevention is key, scientists say, because once ecosystems pass their tipping point(临界点), it is remarkably difficult for them to return.
1.What have scientists discovered with the help of mathematical models of food webs?
A.The living habits of species in food webs.
B.The rules governing food webs of the ecosystems.
C.The approaches to studying the species in the ecosystems.
D.The differences between weak and strong links in food webs.
2.A strong link is found between two species when a predator ________.
A.has a wide food choice
B.can easily find new prey
C.sticks to one prey species
D.can quickly move to another place
3.What will happen if the populations of top predators in a food web greatly decline?
A.The prey species they directly attack will die out.
B.The species they indirectly attack will turn into top predators.
C.The living environment of other species will remain unchanged.
D.The populations of other species will experience unexpected changes.
4.What conclusion can be drawn from the examples in Paragraph 4?
A.Uncontrolled human activities greatly upset ecosystems.
B.Rapid economic development threatens animal habitats.
C.Species of commercial value dominate other species.
D.Industrial activities help keep food webs stable.
5.How does an early-warning system help us maintain the ecological balance?
A.By getting illegal practices under control.
B.By stopping us from killing large predators.
C.By bringing the broken-down ecosystems back to normal.
D.By signaling the urgent need for taking preventive action.
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How does an ecosystem(生态系统)work？What makes the populations of different species the way they are？Why are there so many flies and so few wolves？To find an answer，scientists have built mathematical models of food webs，noting who eats whom and how much each one eats.
With such models，scientists have found out some key principles operating in food webs. Most food webs，for instance，consist of many weak links rather than a few strong ones. When a predator(掠食动物)always eats huge numbers of a single prey(猎物)，the two species are strongly linked；when a predator lives on various species，they are weakly linked. Food webs may be dominated by many weak links because that arrangement is more stable over the long term. If a predator can eat several species，it can survive the extinction(灭绝)of one of them. And if a predator can move on to another species that is easier to find when a prey species becomes rare，the switch allows the original prey to recover. The weak links may thus keep species from driving one another to extinction.
Mathematical models have also revealed that food webs may be unstable，where small changes of top predators can lead to big effects throughout entire ecosystems. In the 1960s，scientists proposed that predators at the top of a food web had a surprising amount of control over the size of populations of other species---including species they did not directly attack.
And unplanned human activities have proved the idea of top-down control by top predators to be true. In the ocean，we fished for top predators such as cod on an industrial scale，while on land，we killed off large predators such as wolves. These actions have greatly affected the ecological balance.
Scientists have built an early-warning system based on mathematical models. Ideally，the system would tell us when to adapt human activities that are pushing an ecosystem toward a breakdown or would even allow us to pull an ecosystem back from the borderline. Prevention is key，which scientists says because once ecosystems pass their tipping point(临界点)，it is remarkably difficult for them to return.
1.What have scientists discovered with the help of mathematical models of food webs？
A.The living habits of species in food webs.
B.The rules governing food webs of the ecosystems.
C.The approaches to studying the species in the ecosystems.
D.The differences between weak and strong links in food webs.
2.A strong link is found between two species when a predator______
A.has a wide food choice B.can easily find new prey
C.sticks to one prey species D.can quickly move to another place
3.What conclusion can be drawn from the examples in Paragraph 4？
A.Uncontrolled human activities greatly upset ecosystems.
B.Rapid economic development threatens animal habitats.
C.Species of commercial value dominate other species.
D.Industrial activities help keep food webs stable.
4.How does an early-warning system help us maintain the ecological balance？
A.By getting illegal practices under control.
B.By stopping us from killing large predators.
C.By bringing the broken-down ecosystems back to normal.
D.By signaling the urgent need for taking preventive action.
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People __1._ (live) in different countries made different kinds of words. Today there are about fifteen hundred _2.___ in the world. Each contains many thousands of words. A very large dictionary, for example, contains four _3.___ five hundred thousand words. But we do not need _4.__these. To read short stories you need to know only about two thousand words. _5._ you leave school, you will learn only one thousand or more.
The words you know are called your vocabulary. You should try to make your vocabulary 6._ (big). Read as many books as we can. There are a lot of books _7.__ (write) in easy English. You will enjoy them. When you come across _8.__ new word, look it _9.___ in your dictionary. Your dictionary is your _10._ (much) useful book.
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They supply Chinese tea and there are several kinds of different _________according to different seasons and personal interests.
A. hobby B. choice C. taste D. love
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They supply Chinese tea and there are several kinds of different _________according to different seasons and personal interests.
A. hobby B. choice C. taste D. love
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People __1.___________ (live) in different countries made different kinds of words. Today there are about fifteen hundred __2.________ in the world. Each contains many thousands of words. A very large dictionary, for example, contains four __3.__________ five hundred thousand words. But we do not need __4.________ these. To read short stories you need to know only about two thousand words. __5._________ you leave school, you will learn only one thousand or more.
The words you know are called your vocabulary. You should try to make your vocabulary __6.____________ (big). Read as many books as we can. There are a lot of books __7.___________ (write) in easy English. You will enjoy them. When you come across __8.___________ new word, look it ___9.____________ in your dictionary. Your dictionary is your __10.__________ (much) useful book.
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Throughout your life you will have many different kinds of relationships. Some relationships are casual and some are close. Strong, close relationships are fulfilling(有意义的). Most people need at least a few relationships of this type.
Ben liked to tell this story about his good friend Isaac: “Once after a big storm, tree branches were all over the yard, which meant I had a full morning of work. Then Isaac came, saying that since I had offered to drive us to the football game that afternoon, he wanted to save me the trouble of picking him up. He was three hours early, however, and he ‘just happened’ to have a rake(耙子) and heavy work gloves with him.”
Isaac showed he understood a basic principle of strong relationships: both sides give as well as receive, otherwise the relationship is unlikely to last.
In strong relationships, giving and getting are united. You feel worthy as a person when you have something to give. When you receive, you give thanks and show appreciation. The cycle of giving and receiving is on going.
One way to help keep relationships strong is to give a word of thanks to anyone who helps you. People can feel hurt if their help isn't acknowledged. For example, Amrit was growing frustrated because Curtis kept calling for help with his homework. So one day when Curtis called, he even thought about telling his brother to say that he wasn't at home. He was glad he didn't. Curtis had called to say how well he had done in his test and to thank Amrit for his help. Saying those two simple words-“Thank you”-can carry a relationship through rough times.
1.What's the author's purpose of mentioning Ben's good friend, Isaac’s story?
A. To explain strong relationships are based on both sides' giving and receiving.
B. To convince the readers that Isaac is one of Ben's trustworthy friends
C. To show that Ben owns the strongest relationship with Isaac.
D. To show what a close relationship can bring to both sides.
2.What does the underlined phrase “on going” in Paragraph 4 mean?
A. Getting around. B. Continuous.
C. Moving forward. D. Unavoidable.
3.The passage mainly tells us ________.
A. some examples of giving and receiving
B. people need different types of relationships
C. how to build and keep strong relationships through giving and receiving
D. one should remember to give thanks to others from time to time
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Different kinds of soil conservation methods are used by farmers to protect their land from damage by farming and the forces of nature. One important form of soil conservation is the use of windbreaks.
Windbreaks are barriers (屏障) formed by trees and other plants with many leaves. Farmers plant them in lines around their fields. Windbreaks stop the wind from blowing soil away. They also keep the wind from destroying or damaging crops. They are very important for growing grains, such as wheat.
There have been studies done on windbreaks in parts of West Africa, for example. They found that grain harvests can be twenty percent higher in fields protected by windbreaks compared to fields without such protection.
However, windbreaks seem to work best when they allow a little wind to pass through. If the wall of trees and plants stops wind completely, then violent air motions will take place close to the ground. These motions will lift soil into the air where it will be blown away. For this reason, a windbreak is best if it has only sixty to eighty percent of the trees and plants needed to make a solid line.
There should be at least two lines in each windbreak. One line should be large trees. The second line, right next to it, can be shorter trees and other plants with leaves. Locally grown trees and plants are best for windbreaks.
1.What is a windbreak according to the passage?
A. A windbreak is a concrete wall to prevent the strong winds.
B. A windbreak is a wood with different kinds of trees.
C. A windbreak is a wall of trees to hold soil in place.
D. A windbreak is a wall of wind to fight wind from the opposite way.
2.When can windbreaks be most effective?
A. The trees are planted one by one.
B. The trees and plants grow in a line.
C. The trees grow as high as they can.
D. Windbreaks allow a little wind to blow through.
3.Which of the following statements is NOT true?
A. A windbreak is one of the best forms of soil conversation.
B. A windbreak is very good for growing grains such as wheat.
C. One line of trees is enough for soil protection.
D. Locally grown trees and plants are the top choice for a windbreak.
world.