Big trees are incredibly important ecologically. For a start, they provide food for countless other species and shelter for many animals. With their tall branches in the sun, they capture vast amounts of energy. This allows them to produce massive crops of fruit and flowers that sustain much of the animal life in the forest.
Only a small number of tree species have the genetic ability to grow really big. The biggest are native to North America, but big trees grow all over the globe, from the tropics to the forests of the high latitudes (纬度). To achieve giant size, a tree needs three things: the right place to establish its seedling, good growing conditions and lots of time with low adult death rate. Lose any of these, and you will lose your biggest trees.
In some parts of the world, populations of big trees are dwindling(逐渐变少) because their seedlings cannot survive. In southern India, for instance, an aggressive non-native bush, Lantana camara, is invading the floor of many forests. Lantana grows so thickly that young trees often fail to take root. With no young trees to replace them, it is only a matter of time before most of the big trees disappear.
Without the right growing conditions, trees cannot get really big and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm. Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there declines markedly in warmer years. “During the day, their growth shuts down when it gets too warm, and at night they consume more energy because their metabolic (新陈代谢) rate increases,” explains David Clark. With less energy produced in warmer years and more being consumed just to survive, there is even less energy available for growth.
The Clarks’ theory, if correct, means tropical forests would shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced. According to the Clarks, this might cause a destabilization(不稳定) of the climate; as older trees die, forests would release some of their stored carbon into the atmosphere, causing a cycle of further warming, forest shrinkage and carbon emissions.
Besides, big trees face threats from elsewhere.
1.According to the passage, big trees make great contributions to the ecosystem because .
A. they can capture large amounts of energy.
B. they determine the change of global climate.
C. they provide the essentials for many creatures.
D. they can avoid a new cycle of further warming.
2.All the following factors are a must for making big trees EXCEPT .
A. no deadly damage B. genetic contribution
C. ideal environment for growth D. high-latitude location
3.What is the best title of the passage?
A. Big trees in trouble. B. Advantages of big trees.
C. Results of big trees’ disappearing. D. Importance of big trees to humans.
4.What will the author most probably discuss after the last paragraph?
A. More threats to the existence of big trees.
B. The effect of human activities on big trees.
C. Benefits of big trees to the whole atmosphere.
D. Comparison between common trees and big ones.
高二英语阅读理解中等难度题
Big trees are incredibly important ecologically. For a start, they provide food for countless other species and shelter for many animals. With their tall branches in the sun, they capture vast amounts of energy. This allows them to produce massive crops of fruit and flowers that sustain much of the animal life in the forest.
Only a small number of tree species have the genetic ability to grow really big. The biggest are native to North America, but big trees grow all over the globe, from the tropics to the forests of the high latitudes (纬度). To achieve giant size, a tree needs three things: the right place to establish its seedling, good growing conditions and lots of time with low adult death rate. Lose any of these, and you will lose your biggest trees.
In some parts of the world, populations of big trees are dwindling(逐渐变少) because their seedlings cannot survive. In southern India, for instance, an aggressive non-native bush, Lantana camara, is invading the floor of many forests. Lantana grows so thickly that young trees often fail to take root. With no young trees to replace them, it is only a matter of time before most of the big trees disappear.
Without the right growing conditions, trees cannot get really big and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm. Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there declines markedly in warmer years. “During the day, their growth shuts down when it gets too warm, and at night they consume more energy because their metabolic (新陈代谢) rate increases,” explains David Clark. With less energy produced in warmer years and more being consumed just to survive, there is even less energy available for growth.
The Clarks’ theory, if correct, means tropical forests would shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced. According to the Clarks, this might cause a destabilization(不稳定) of the climate; as older trees die, forests would release some of their stored carbon into the atmosphere, causing a cycle of further warming, forest shrinkage and carbon emissions.
Besides, big trees face threats from elsewhere.
1.According to the passage, big trees make great contributions to the ecosystem because .
A. they can capture large amounts of energy.
B. they determine the change of global climate.
C. they provide the essentials for many creatures.
D. they can avoid a new cycle of further warming.
2.All the following factors are a must for making big trees EXCEPT .
A. no deadly damage B. genetic contribution
C. ideal environment for growth D. high-latitude location
3.What is the best title of the passage?
A. Big trees in trouble. B. Advantages of big trees.
C. Results of big trees’ disappearing. D. Importance of big trees to humans.
4.What will the author most probably discuss after the last paragraph?
A. More threats to the existence of big trees.
B. The effect of human activities on big trees.
C. Benefits of big trees to the whole atmosphere.
D. Comparison between common trees and big ones.
高二英语阅读理解中等难度题查看答案及解析
阅读下列短文，从每题所给的四个选项(A、B、C和D)中,选出最佳选项。
Big trees are incredibly important ecologically. For a start, they provide food for countless other species and shelter for many animals. With their tall branches in the sun, they capture vast amounts of energy. This allows them to produce massive crops of fruit and flowers that sustain much of the animal life in the forest.
Only a small number of tree species have the genetic ability to grow really big. The biggest are native to North America, but big trees grow all over the globe, from the tropics to the forests of the high latitudes(纬度). To achieve giant size, a tree needs three things: the right place to establish its seeding, good growing conditions and lots of time with low adult death rate. Lose any of these, and you will lose your biggest trees.
In some parts of the world, populations of big trees are dwindling because their seedings cannot survive. In southern India, for instance, an aggressive non-native bush, Lantana camara, is invading the floor of many forests. Lantana grows so thickly that young trees often fail to take root. With no young trees to replace them, it is only a matter of time before most of the big trees disappear.
Without the right growing conditions, trees cannot get really big and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm. Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there declines markedly in warmer years. “During the day, their growth shuts down when it gets too warm, and at night they consume more energy because their metabolic(新陈代谢的)rate increases,” explains David Clark. With less energy produced in warmer years and more being consumed just to survive, there is even less energy available for growth.
The Clarks’ theory, if correct, means tropical forests would shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced. According to the Clarks, this might cause a destabilization of the climate; as older trees die, forests would release some of their stored carbon into the atmosphere, causing a cycle of further warming, forest shrinkage and carbon emissions.
Besides, big trees face threats from elsewhere.
1. All the following factors are a must for making big trees EXCEPT_________.
A. genetic contribution
B. no deadly damage
C. ideal environment for growth
D. right place to establish its seeding
2.The word “dwindling”(paragraph3) is closest in meaning to “_______”.
A. exploding B. decreasing
C. changing D. growing
3. What is the best title of the passage?
A. Results of big trees’ disappearing.
B. Advantage of big trees.
C. Big trees in trouble
D. Importance of big trees to humans.
4.What will the author most probably discuss after the last paragraph?
A. Comparison between common trees and big ones.
B. The effect of human activities on big trees.
C. Benefits of big trees to the whole atmosphere.
D. More threats to the existence of big trees.
高二英语阅读理解中等难度题查看答案及解析
Big trees are very important in ecology. For a start, they provide food for countless other species and shelter for many animals. With their tall branches in the sun, they take in vast amounts of energy. This allows them to produce massive crops of fruit and flowers that much of the animal life in the forest feed on.
Only a small number of tree species have the genetic(基因的) ability to grow really big. The biggest are native to North America, but big trees grow all over the globe, from the tropics(热带地区) to the forests of the high latitudes(纬度). To achieve giant size, a tree needs three things: the right place to establish(建立) its seedling, good growing conditions and lots of time with low adult death rate. Lose any of these, and you will lose your biggest trees.
In some parts of the world, populations of big trees are dwindling because their seedlings cannot survive. In southern India, for instance, an aggressive non-native bush, Lantana camara, is invading the floor of many forests. Lantana grows so thickly that young trees often fail to take root. With no young trees to replace them, it is only a matter of time before most of the big trees disappear.
Without the right growing conditions, trees cannot get really big and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm. Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there slows obviously in warmer years. “During the day, their growth shuts down when it gets too warm, and at night they consume more energy because their metabolic(新陈代谢的) rate increases,” explains David Clark. With less energy produced in warmer years and more being consumed just to survive, there is even less energy available for growth.
The Clarks’ theory, if correct, means tropical forests would be smaller over time. The largest, oldest trees would gradually die off and tend not to be replaced. According to the Clarks, this might cause a destabilization of the climate; as older trees die, forests would release some of their stored carbon into the atmosphere, causing a cycle of further warming, forest shrinkage and carbon emissions.
Besides, big trees face threats from elsewhere.
1.According to the passage, big trees make great contributions to the ecosystem because ________.
A. they can take in large amounts of energy
B. they determine the change of global climate
C. they provide the essentials for many creatures
D. they can improve a new cycle of further warming
2.All the following factors are a must for making big trees EXCEPT ______.
A. no deadly damage
B. the suitable place for new plants’ growing
C. good environment for growth
D. the highest location
3.The word “dwindling” (paragraph3) is closest in meaning to “______”.
A. exploding B. growing
C. changing D. dropping
4.What is the best title of the passage?
A. Big trees in trouble.
B. Advantages of big trees.
C. Results of big trees’ disappearing.
D. Importance of big trees to humans.
5.What will the author most probably discuss after the last paragraph?
A. More threats to the existence of big trees.
B. The effect of human activities on big trees.
C. Benefits of big trees to the whole atmosphere.
D. Comparison between common trees and big ones.
高二英语阅读理解中等难度题查看答案及解析
Inner Mongolia Autonomous Region is an important ecological screen for the north of China and even the whole country. Building a green great wall to ensure China’s ecological security is one of the most important things of autonomous region.
The largest ecological function zone in the north of China, Inner Mongolia has a variety of landscapes, including forests, grasslands, wetlands, rivers and lakes. In recent years, the region’s environment has improved, with its forest and grassland area having increased and desert reduced.
However, it still faces a number of challenges in ecological preservation. For instance, the region faces severe water shortages with the number of lakes dropping from 427 in 1987 to 145 in 2010. In addition to a lack of rainfall, huge water consumption in agricultural and industrial production has worsened the water shortage. Too much use of fertilizers has damaged the soil and affected the growth of grass, accelerating the expansion of the desert, which results from a lack of water.
The local government encourages planting trees on grassland as they can get more pay for trees than by growing grass. However, the trees they plant often have a low survival rate as they have a high water consumption rate. Also, to treat wetlands, some areas have planted a large number of a single tree species. This practice may damage biodiversity (生物多样性) and endanger the survival of certain animals.
Experts suggest taking the region’s water resources and weather conditions into consideration in future ecological projects.
1.What do we know about the green great wall in Inner Mongolia Autonomous Region?
A. It adds the beautiful scenery to this area.
B. It acts as a guard to protect the north of China.
C. It works well in saving the endangered animals.
D. It contributes to the decrease of the grassland.
2.What does the third paragraph mainly talk about?
A. The causes of water shortages. B. The protection of ecological environment.
C. The solutions to water shortages. D. The importance of ecological environment.
3.What does the underlined word “accelerating” in Paragraph 4 probably mean?
A. weakening B. shortening
C. lessening D. quickening
4.What’s the author’s purpose of writing the text?
A. To tell the function of the green great wall.
B. To introduce the green great wall to the readers.
C. To provide guidance on traveling around Inner Mongolia.
D. To offer some advice on building the green great wall.
高二英语阅读理解中等难度题查看答案及解析
Trees are useful to man in three important ways: They provide him with wood and other products; they provide him shade;. and they help to prevent droughts（早灾）and floods.
Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important．In his eagerness to make money from trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had. And besides, he is usually too careless to plant and look after new trees. So the forests slowly disappear.
This does not only mean that man will have fewer trees. The results are even more serious: for where there are trees, their roots break up soil allowing the rain to sink in and also bind（固定）the soil, thus preventing it from being washed away easily；but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When the top-soil is gone, nothing remains but worthless desert.
Two thousand years ago，a rich and powerful country cut down its trees to build warships, with which to gain itself an empire(帝国）．It set up the empire, but, without its trees, its soil became poor and grew weak. When the empire fell to pieces, the home country found itself faced by floods and starvation（饥荒）．
1.The most important service of trees to man is that___________．
A. they give them wood and other products B. they give them shade
C. they help him prevent droughts and floods D. they help him made money
2.In many parts of the world, forests slowly disappear because___________．
A. many trees have been cut down by man B. man has not paid enough attention to planting trees
C. new trees are not looked after properly D. all the above
3.Land becomes desert after all trees are cut down because____________．
A. roots of trees break up the soil B. there are too many rainfalls
C. there are no larger trees to keep rain and protect the top-soil D. strong winds bring a lot of sand
4.The country mentioned in the passage suffered from floods and starvation because________.
A. it set up an empire B. the empire fell to pieces
C. it built too many warships D. it lost its trees
5.Which title best fits the passage?
A. Trees and Man B. How Trees Prevent Droughts and Floods
C. How an Empire Fell D. A Story about Trees.
高二英语阅读理解中等难度题查看答案及解析
As we all know ,trees are important to our life. They provide us with food, wood and most importantly, oxygen. Now there is one more thing we can add to this list—blocking out harmful bacteria in water.
The discovery was made by some scientists and high school students who were seeking for a natural water filter(过滤器)—one that could help people in developing countries that don’t have access to modern water systems.
The researchers, led by Rohit Karnik, a professor ,decided to turn to trees for help because they were able to allow liquid to flow through while blocking out air bubbles(气泡）.
They began by cutting 1.5-inch-wide sections of tree bark from the branch of a white pine tree. The researchers then tested the wood’s filtering ability by pouring water containing red dye particles(染料颗粒)of different sizes through. To their surprise, they found it was effective in trapping all the particles. Encouraged, the team did another experiment, this time with water containing bacteria. Sure enough, the bark held back 99%of the bacteria, allowing only 1% to flow through.
Mr. Karnik said the bark was able to filter water containing much smaller particles. This means that it can be used to get rid of most of the bacteria. However, what troubles them is that tree bark cannot hold back viruses, which tend to be much smaller.
Though the experiment is successful, we must remember one thing—the bark only works when damp. This means that before this natural filter can be put to practical use, the researchers will have to figure out how to keep the bark damp, or find a way to keep the bark’s great filtering ability even when it’s dry.
But the study is not done. The researchers plan on testing other types of trees, including those flowering trees. They think those may be more effective in trapping smaller particles and even viruses.
1.How will the discovery affect the world?
A. No harmful bacteria will be found in water.
B. There will be no water pollution around the world.
C. More pine trees will be planted around the world.
D. Clean water will be more accessible in developing countries.
2.What problem troubles the researchers when using the trees bark as a water filter?
A. Viruses cannot be prevented.
B. Tree bark should be wet.
C. It’s hard to remove air bubbles.
D. Not all bacteria can be held back.
3.Why does the team plan to do other experiments?
A. To find other natural water filters.
B. To improve the filtering ability of other trees.
C. To find a way to keep the bark wet.
D. To test the filtering ability of other trees.
4.In which column of a newspaper can we read this text?
A. Culture. B. Science.
C. Lifestyle. D. Society.
高二英语阅读理解中等难度题查看答案及解析
We can’t deny that trees are useful to man in three very important ways: they provide him with wood and other products, they give him shade, and they help to prevent drought and floods.
Unfortunately, in many parts of the world man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had.
Two thousand years ago a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees, its soil became hard and poor. When the empire fell to pieces, the country found itself faced by floods and starvation.
Even though a government realizes the importance of a plentiful supply of trees, it is difficult for it to persuade the villager to see this. The villager wants wood to cook his food, and he can earn money by making charcoal or selling wood to the townsman. He is usually too lazy or too careless to plant and look after trees. So unless the government has a good system of control, or can educate the people, the forests will slowly disappear.
This does not only mean that the villagers’ sons and grandsons have fewer trees. The results are even more serious. For where there are trees ,their roots break the soil up, allowing the rain to sink in and also bind the soil, thus preventing it being washed away easily, but where there are no trees, the soil becomes hard and poor. The rain falls on hard ground and flows away on the surface, causing floods and carrying away the rich topsoil, in which crops grow so well. When all the topsoil is gone, nothing remains but worthless desert.
1.It’s a great pity that ________.
A. man is only interested in building empires
B. man is eager to profit from trees
C. man hasn’t realized the importance of trees to him
D. man hasn’t found out that he has lost all trees
2.Sooner or later the forests will disappear______
A. unless people are taught the importance of planting trees
B. unless people stop cutting down their trees
C. unless a county has a plenty supply of trees
D. unless the government punishes those who cut trees instead of planting trees
3.The word “bind” in Paragraph 5 means”_________”
A. to make stay together B. to make wet
C. to wash away D. to improve
4.When there is a heavy rain ,trees can help to prevent floods, as they can ___________
A. keep rain from falling down to soft ground
B. cause the soil to allow rainwater to sink in
C. prevent the soil from being washed away
D. make the topsoil stick together
高二英语阅读理解中等难度题查看答案及解析
Green tree ants are important builders in the rainforest. They’re like the worker bees of the ant world. The native forest of Thala Beach Nature Reserve is the natural home of these insects.
They climb all over the tree that contains their nest and protect it from enemies with great fierceness. The ants are often in the fruiting trees of Tropical North Queensland. When an animal tries to help themselves to some tasty fruit, they find themselves attacked by a powerful, frightening army of green tree ants! Their bite is not very painful but many ants attacking at the same time can be extremely uncomfortable.
The nests are large and constructed by sticking the leaves at the end of branches together to create a home looking roughly like a globe. Most of the nest construction and weaving is conducted at night. A mature colony of green tree ants can hold as many as 100,000 to 500,000 workers and may include as many as 12 trees and contain as any as 150 nests. Green tree ant colonies have one queen and a colony can live up to eight years.
However, the ants are so busy that they fail to spot a dishonest figure. There is a spider called the Salticid spider, or the jumping spider, as they are sometimes referred to, which has excellent eyesight and is only active during daylight, weaving a protective covering of silk to spend the night in. Interestingly, the Salticid spider does not look like a green tree ant. Instead, it chemically copies green tree ants’ smell. Effectively pretending to be an ant, it goes into the green tree ants’ nest, enters the nursery and feasts on their babies. Green tree ants don’t have good eyesight and smell everything with their antennae (two long thin parts on an ant’s head). Therefore, the ants think the spider is another ant and ignore its presence within the nest.
Next time, as you wander around Thala’s native forest, keep an eye out for these busy little creatures. Look up into the trees and you’ll likely spot their nests.
1.What does Paragraph 2 tell us about green tree ants?
A. They often start wars for food. B. They like tasty fruit very much.
C. They leave painful bites. D. They have good defenses.
2.What is special about the green tree ant’s nest?
A. It takes years to weave a nest. B. It is reconstructed yearly.
C. It is made of leaves. D. It can hold up to 500,000 ants.
3.Why do green tree ants regard the spider as another ant?
A. It can communicate with them. B. It can make familiar sounds.
C. It has a similar smell. D. It has an ant’s appearance.
4.What can we say about the Salticid spider?
A. It is the green tree ant’s enemy. B. It helps the green tree ant build bests.
C. It is harmful to fruiting trees. D. It protects the green tree ant.
高二英语阅读理解中等难度题查看答案及解析
Developing healthy eating habits starts from childhood, therefore it is important for parents to teach and provide children with a healthy diet. DPHSS administrator of the Bureau of Nutrition Services, Charlie Morris told KUAM News, “A healthy diet for a child consists of a lot of fruits and vegetables in the diet limiting the amount of simple sugars in the diet and high fat food and highly processed food.”
This means staying away as much as possible from food such as chips, cookies, candies and sugary drinks, as all children need to have meals which involve a well-balanced diet. Community nutritionist Thelma Romoso said, “The fruit, the vegetable, the grain, the protein, and also the milk, the diary product, so for the fruits it’s easy for a mother to go into the two plus three concept of fruits and vegetables or five a day.”
This concept means that there are at least two servings of fruits a day, three servings of vegetables a day which can be served for lunch and dinner. As for protein parents can make a variety of dishes from chicken, beef, fish or even dried beans to pledge the child gets three servings a day.
Morris said that the child’s hunger level controls how much is eaten and the parent controls what and when the meal is offered, saying, “Mom needs to ensure that the food offered is good food for the child to eat and throughout the day depending on how active they are, snacks are not a bad thing, so the mom should offer good kinds of snacks.”
When it comes to preparing your child’s lunch and snacks for school, make sure to keep in mind that the food you provide should not only be a source of energy but also be nutritionally beneficial such as fresh fruits, and whole grain bread. But parents must be sure to remember that a good nutritional diet must be balanced with physical activity, namely it is important that children get outside and run around and play and get activity in addition to eating a good diet.
1.What does the author intend to tell us in the passage?
A. Choose healthy food and snacks for your child.
B. Fruits and vegetables are good for your child.
C. Take steps to provide a good lunch for your child.
D. Make various and delicious dishes for your child.
2.According to Charlie Morris we can know that_________.
A. mothers should prepare delicious food by themselves
B. highly processed food should be reduced in daily life
C. sugars and high fat exist in few kinds of food
D. active children prefer more and more snacks
3.It can be inferred from the passage that _________.
A. fresh fruits are often ignored by children
B. a good nutritional diet may cost too much
C. choosing healthy food is linked with income
D. parents play a very important role in children’s healthy diet
高二英语阅读理解困难题查看答案及解析
阅读理解。
Developing healthy eating habits starts from childhood, therefore it is important for parents to teach and provide children with a healthy diet. DPHSS administrator of the Bureau of Nutrition Services, Charlie Morris told KUAM News, “A healthy diet for a child consists of a lot of fruits and vegetables in the diet limiting the amount of simple sugars in the diet and high fat food and highly processed food.”
This means staying away as much as possible from food such as chips, cookies, candies and sugary drinks, as all children need to have meals which involve a well-balanced diet. Community nutritionist Thelma Romoso said, “The fruit, the vegetable, the grain, the protein, and also the milk, the diary product, so for the fruits it’s easy for a mother to go into the two plus three concept of fruits and vegetables or five a day.”
This concept means that there are at least two servings of fruits a day, three servings of vegetables a day which can be served for lunch and dinner. As for protein parents can make a variety of dishes from chicken, beef, fish or even dried beans to pledge the child gets three servings a day.
Morris said that the child’s hunger level controls how much is eaten and the parent controls what and when the meal is offered, saying, “Mom needs to ensure that the food offered is good food for the child to eat and throughout the day depending on how active they are, snacks are not a bad thing, so the mom should offer good kinds of snacks.”
When it comes to preparing your child’s lunch and snacks for school, make sure to keep in mind that the food you provide should not only be a source of energy but also be nutritionally beneficial such as fresh fruits, and whole grain bread. But parents must be sure to remember that a good nutritional diet must be balanced with physical activity, namely it is important that children get outside and run around and play and get activity in addition to eating a good diet.
1.What does the author intend to tell us in the passage?
A. Choose healthy food and snacks for your child.
B. Fruits and vegetables are good for your child.
C. Take steps to provide a good lunch for your child.
D. Make various and delicious dishes for your child.
2.According to Charlie Morris we can know that_________.
A. mothers should prepare delicious food by themselves
B. highly processed food should be reduced in daily life
C. sugars and high fat exist in few kinds of food
D. active children prefer more and more snacks
3.It can be inferred from the passage that _________.
A. fresh fruits are often ignored by children
B. a good nutritional diet may cost too much
C. choosing healthy food is linked with income
D. parents play a very important role in children’s healthy diet
高二英语阅读理解中等难度题查看答案及解析