英语专四 听力

21. SoilsThere are many different kinds of soils. Different soils have different types of rock and minerals in them. Some soils have more water in them than others. Some soils might have more plant and animal material in them, too.Different kinds of soils are found in different parts of the world. There are several kinds of soils found in the United States. In some areas, the soil has a lot of clay. Other soils are very sandy. Loam is a kind of soil that has a good mixture of clay and sand.In some places, soil layers are very thick. Lots of plants grow in places with a thick soil layer. In dry and windy places soil layers are much thinner. Layers of soil on mountains are thin because gravity pulls the soil downhill.The type of soil in a particular place affects what kinds of plants can grow there. Useful Words:1. clay 黏土，泥土2. loam 肥土3. layer 层4. gravity 地心引力，重力5. downhill 往下 22. CrisisLife is a contest! Who will win? A bluebird and sparrow both compete for space to build their nests. A fast-growing maple tree and slower-growing dogwood compete for the sunlight they both need. Oil competes with coal and nuclear power as an energy source for electric power plants!There is a problem. There is a limited amount of space for birds, sunlight for trees, and energy for people! If we do not cut back on our uses of some of our resources, someday they will be gone!How can we use energy today and know we will have enough to go around in the future? We can choose alternate, or replacement, energy resources. It takes the earth millions of years to create coal, oil, and gas. They are nonrenewable resources.Solar energy, wind energy and water energy are renewable resources. It takes the earth millions of years to create coal, oil, and gas. They are nonrenewable resources.Solar energy, wind energy and water energy are renewable. What other ways can we conserve our sources? How can we make sure there is always enough to go around? Useful words and expressions:1. bluebird 蓝知更鸟2. sparrow 麻雀3. dogwood 山茱萸4. power plant 发电厂，发电站5. alternate 替换物6. nonrenewable resources 不可再生资源7. conserve 保存，保藏 23. America’s Worst SurpriseDecember 7, 1941 was one of the worst days in American history. Nearly all Americans who are old enough to remember that day can still remember what they were doing at the moment they heard “the news”. The news was that America had been attacked!Shortly before 2:00 P.M., a radio dispatch came into Washington from Honolulu, Hawaii. “Air Raid, Pearl Harbor— This is no drill.” Japanese planes had begun an attack on the largest American military base in the Pacific. They first destroyed planes on the ground. Then they bombed the ships in the harbor.No one had expected the attack. So no one was prepared for it. And it did not take long for Japanese to do their damage. When the smoke cleared, the Navy counted its losses. Eighteen ships had been sunk or badly damaged. Nearly 150 planes had been destroyed. More than 2,400 Americans had been killed and more than 1,200 wounded.Useful Words and Expressions:1. dispatch 派遣，急件2. air raid 空袭3. drill 军事训练，操练4. Pearl Harbor 珍珠港 24. Great Depression in the U.S. In 1929, the bill started to come in. American industry had produced too many goods. Americans could not afford t