2. 外语
  3. Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. Fo

Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. Fo

admin2010-01-26  43
问题 Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1.
For questions 1-4, mark
Y (for YES)            if the statement agrees with the information given in the passage;
N (for NO)             if the statement contradicts the information given in the passage;
NG (for NOT GIVEN)     if the information is not given in the passage.
For questions 5-10, complete the sentences with the information given in the passage.
                                    The Choice: Doomsday or Arbor Day
    Environmental issues affect every life on this planet from the smallest parasite to the human race. The reason for this is simple. A single disruption in the Earth’s delicate balance can mean certain destruction of the very place that cradles the lives of many species. One such issue that requires consideration is deforestation. Trees have been or are being cut down at increasingly high rates. If this is not stopped many unfavorable and irreversible effects could result.
Why Trees Matter
    To understand why deforestation is such a pressing and urgent issue, forests must first be given credit for what they bring to global ecosystems and the quality of life that all species maintain. Tropical Rainforests presently give a place to call home for 50%—90% of all organisms, 90% of our relatives, the primates, and 50 million creatures that can live no place but the rich rainforests. Not only are other species at risk, but the human race also benefits from what the trees give. From something as minor as the spices that indulge food to life-giving medicines, the rainforests amplify and save lives. The forests give life, not only to other species, but they help to prolong the human race.
Population Growth and Deforestation
    So this leads into a very confusing question of the 20th century. Why are these trees being torn down? The World Wide Forest Report found that when the Roman Empire was in control of Europe 90% of the continent was forested. Today 500,000 hectors vanish in a single week. There is no one easy answer as there are many causes at the root of deforestation. One is overpopulation in cities and developing countries. Population is continually growing in the third world. Some had land until increases in population forced them off it and they became landless peasants that are forced to look for land in the untouched forests. This movement to the forests is in some ways a result of government pressures. In place of implementing programs to help the poor these governments concentrate on the cheapest and easiest way to keep poverty out of sight and give the poor no other choice but to force other species out and themselves in. The poor are pushed in further and further and destroy more every time they must move on.
Logging and Deforestation
     The small farmer plays a big role, but it is modem industry that too cuts down the trees. The logging industry is fueled by the need for disposable products. 11 million acres a year are cut for commercial and property industries. Peter Heller found that McDonald’s needs 800 square miles of trees to make the amount of paper they need for a year’s supply of packaging. British Columbia is reported to manufacture 7, 500,000 pairs of chopsticks a day, and there is also the high demand for fuel wood. Logging does too have its repercussions(影响).
Cattle Grazing and Deforestation
    Another of the more devastating forces behind deforestation is cattle grazing. With the international growth of fast food chains this seems to be an evident factor in the clearing of trees today. Large corporations looking to buy beef for hamburger and even pet food seek cheap prices and are finding them with the growth of cattle grazing. In the Amazon region of South America alone there are 100,000 beef ranchers. As the burger giants of industrialized society are making high demands for more beef, more forests are being torn down. Statistics from less than a decade ago, 1989, indicate that 15,000 km squared of forests are used expressly for the purpose of cattle grazing. Once the trees are gone the land is often overgrazed.
Other Causes
    Beyond the major causes of deforestation lie some supplementary ones that too stack the odds against forests around the globe. Acid rain and the building of dams have their share of harmful effects. The race to produce cash crops such as fruit, spices, sugar, tobacco, soap, rubber, paper, and cloth has given cause to many to try to farm them by using soil and other products that can be retrieved by destroying the forests.
The Effects
    Deforestation presents multiple social and environmental problems. The immediate and long-term consequences of global deforestation are almost certain to jeopardize life on Earth, as we know it.
What is Lost
    Deforestation is causing a loss of biological diversity on an unprecedented scale. Although tropical forests cover only six percent of Earth’s land surface, they happen to contain between 70% and 90% of all of the world’s species. As a result of deforestation, we are losing between 50 and 100 animal and plant species each day. Inevitably, the loss of species entails a loss of genetic resources. Many of these species now facing the possibility of extinction are of enormous potential to humans in many areas; especially medicine. As of 1991, over 25% of the world’s pharmaceutical products were derived from tropical plants. By contributing to the extinction of multiple species of plants and animals, we might be destroying the cures for many of the diseases that plague the human race today.
Erosion
    The lushness (茂盛) of the world’s tropical forests is somewhat deceptive. Although these forests assume to be lush and full, the underlying soils are very poor, almost all the nutrients being bound up in the vegetation. The problem is that once forests have been cut down, essential nutrients are washed out of the soil all together. This leads to soil erosion. As of now, about 80% of the soils in the humid tropics are acidic and infertile. When there are no trees to keep the soil in place, the soil becomes ripe for erosion. It dries and cracks under the Sun’s heat, losing its fertility. The soil erosion will lead to permanent impoverishment of huge land areas.
    The social impact of soil erosion can be quite severe. Those who settle into the forest regions are forced to move every year or so due to soil erosion. They find areas where they can cultivate. When those areas are no longer good for growing, they move to another region.
Flooding
    Flooding is a quite serious consequence of deforestation. Clearing the forest dramatically increases the surface ran-off from rainfall, mainly because a greater proportion of the rain reaches the ground due to a lack of vegetation which would suck up the excess rainfall. "Tropical forests can receive as much rain in an hour as London would expect in a wet month, and a single storm has been measured as removing 185 tons of topsoil per hectare". In tropical regions where the forests are dense, flooding is not as serious a problem because there is vegetation to absorb the rainfall. It is in areas where there is little vegetation that there is a problem. Hence, to avoid the disastrous effects of flooding, tropical forests need to remain dense and lush.
Climate Change
    Although all consequences of deforestation are potentially serious, perhaps the most serious consequence is that of climate change due to the loss of trees. Earth has an atmosphere which contains a variety of gases, all in a delicate balance, to ensure life on Earth. One of these gases in Earth’s atmosphere is carbon dioxide, a gas which helps moderate heat loss to outer space. If there are additional greenhouse gases, there will be a gradual increase in temperature on Earth’s surface. This could lead to changes in weather patterns, sea levels, and other cycles in nature that directly affect life on Earth.
    The immediate effects of deforestation may not yet be felt, but if this generation doesn’t feel it the next generation and their children will be the ones to suffer. It is the actions of the human race that can make or break the future of the planet. In the end everyone loses unless a solution can be reached. This is easier said than done but the choices that lie ahead on this matter carry severe consequences that will forever change the way that all things live if they are able to live at all.
With the forests cut down, soil can easily lose its fertility when the essential nutrients are ______.
选项
答案washed out of it
解析
转载请注明原文地址:https://kaotiyun.com/show/gMdK777K
0

大学英语六级

相关试题推荐
随机试题
最新回复(0)