【单选题】【消耗次数:1】
Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).In many places forests slowly disappear because __________.
many trees have been cut down by man
new trees are not well looked after
man has not paid enough attention to planting trees
all the above
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【单选题】 Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).Land becomes desert after all trees are cut down because __________.
①  roots of trees break up the soil
②  no tree keeps the rain and protects the top-soil
③  strong winds bring a lot of sand
④  there are too many rainfalls to make it
【单选题】 Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).Why did the country mentioned in the passage suffer from floods and starvations?
①  Because it set up an empire.
②  Because it fell to pieces.
③  Because it turned its trees into warships.
④  Because it spent too much money on wars.
【单选题】 Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).According to the passage, which is the most important service of trees to man?
①  They help him make money.
②  They give him cool.
③  They give him wood and other things.
④  They help him to stop droughts and floods.
【单选题】 Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).Which title best fits the passage?
①  Trees and Man
②  The Function of Tree Wood
③  How do People do with Trees?
④  The Usage of Tree Roots
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).2. In many places forests slowly disappear because __________.
①  A. many trees have been cut down by man
②  B. new trees are not well looked after
③  C. man has not paid enough attention to planting trees
④  D. all the above
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).3. Land becomes desert after all trees are cut down because __________.
①  A. roots of trees break up the soil
②  B. no tree keeps the rain and protects the top-soil
③  C. strong winds bring a lot of sand
④  D. there are too many rainfalls to make it
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).4. Why did the country mentioned in the passage suffer from floods and starvations?
①  A. Because it set up an empire.
②  B. Because it fell to pieces.
③  C. Because it turned its trees into warships.
④  D. Because it spent too much money on wars.
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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. According to the passage, which is the most important service of trees to man?
①  A. They help him make money.
②  B. They give him cool.
③  C. They give him wood and other things.
④  D. They help him to stop droughts and floods.
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Trees mainly serve man in three important ways: They provide him with wood and other products; they provide him shade; and they help to prevent droughts 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.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).5. Which title best fits the passage?
①  A. Trees and Man
②  B. The Function of Tree Wood
③  C. How do People do with Trees?
④  D. The Usage of Tree Roots
【单选题】 He lives in a village _____there are a lot of trees.
①  there
②  where
③  that
④  which
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①  猪瘟和蓝耳病
②  新城疫和禽流感
③  布病和结核病
④  狂犬病和乙型脑炎
【单选题】 新城疫的主要防制措施是
①  免疫接种
②  预防性投药
③  全进全出
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【单选题】 免疫接种疫苗预防马立克氏病是一种
①  细胞免疫
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③  肿瘤免疫
④  变态免疫
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①  病牛直接传递
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③  鼠类带毒传递
④  昆虫带毒传递
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①  净化种群
②  预防性投药
③  鸡舍内消毒
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①  多杀性巴氏杆菌
②  副鸡嗜血杆菌
③  鸡败血支原体
④  禽腺病毒
⑤  禽呼肠孤病毒
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③  猪流行性腹泻
④  鸡传染性贫血
【判断题】 玉米蛋白质中的第一限制氨基酸为赖氨酸。
①  正确
②  错误