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Wind currents turn out to be more active in colder areas in the northern hemisphere.
A．Y
B．N
C．NG
答案
更多“Wind currents turn out to be more active in colder areas in the northern hemisphere.A．YB．N”相关的问题
第1题
Floods
Water is one of the most useful things on Earth. We drink it, bathe in it, clean with it and use it to cook food. Most of the time, it is completely beneficial to the humans. But in large enough quantities, the very same stuff we use to wash a toothbrush can overturn cars, destroy houses and even kill. Flooding has claimed millions of lives in the last hundred years alone, more than any other weather phenomenon.
How water exists on our planet
The total amount of water on Earth has remained fairly constant for millions of years (though its distribution has varied considerably in that time). Every day, a very small amount of water is lost high in the atmosphere, where intense ultraviolet rays can break a water molecule apart, but new water is also emitted from the inner part of the Earth, by volcanic activity. The amount of water that is created and the amount that is lost are pretty much equal.
At any one time, this volume of water is in many, different forms. It can be liquid, as in oceans, rivers and rain; solid, as in the glaciers of the North and South Poles; or gaseous, as in the invisible water vapor in the air. Water changes from state to state as it is moved around the planet by wind currents.
Wind currents
Wind currents are generated by the heating activity of the sun. The sun shines more on the area around Earth's equator than it does on areas farther north and south, causing a heat discrepancy over the surface of the globe. In warmer regions, hot air rises up into the atmosphere, pulling cooler air into the unoccupied space. In cooler regions, cold air sinks, pushing/driving warmer air into the unoccupied space. The rotation of the Earth breaks this cycle up, so there are several, smaller air-current cycles all along the globe.
Overall, wind currents in the atmosphere are fairly consistent. At any particular time of year, currents tend to move in a certain way across the globe. Consequently, specific locations generally experience the same sort of weather conditions year to year. But on a day-to-day basis, the weather is not so predictable. Wind currents and precipitation(降水) are affected by many factors, chiefly geography and neighboring weather conditions. A huge number of factors combine in an infinite variety of ways, producing all sorts of weather. Occasionally, these factors interact in such a way that an atypical volume of liquid water collects in one area. For example, conditions occasionally cause the formation of a hurricane, which dumps a large quantity of rain wherever it goes. If a hurricane lingers over a region, or multiple hurricanes happen to move through the area, the land receives much more precipitation than normal.
Waterways
Since waterways are formed slowly over time, their size is proportionate to the amount of water that normally accumulates in that area. When there is suddenly a much greater volume of water, the normal waterways overflow, and the water spreads out over the surrounding land, At its most basic level, this is what a flood is—an abnormal accumulation of water in an area of land.
Sources of floods
As has been mentioned above, floods occur when an atypical volume of water collects in an area. There are a number of ways this might happen, and there are a wide range of events that occur when it does.
-Rainstorms
The sort of flooding that most people are familiar with occurs when an unusually large number of rainstorms hit an area in a fairly short period of time. In this case, the rivers and streams that divert the water to the ocean are simply overwhelmed. The varying temperatures of different seasons lead to different weather patterns. In the winter, for example, the air over the ocean might be warmer than the air over the land, causing the wind flow to move from the land out to sea. But in the summer, the air over the land heats
A．Y
B．N
C．NG
第2题
听力原文：M: Hey, Michelle. Look what I just found. Right here in the sand.
W: A piece of wood？ Oh. Driftwood. Interesting shape... Almost like some sort of modern sculpture.
M: Yeah. And feel how smooth it is.
W: Hmm, Must've been in the water a long time. It could've been drifting in the ocean currents for months, or even years.
M: In the currents？ Doesn't the wind just blow things around out there？
W: Well, sure. But the currents are always moving, too. Almost like rivers, but underwater rivers, flowing through the ocean.
M: So how do they find out where these currents go？ Stick a message in a bottle and throw it in the water？
W: Don't laugh. In fact, I was reading in a science magazine that oceanographers have released huge numbers of bottles into the ocean over the years. They wanted to map out where the currents would carry them.
M: Say, I'll bet-after they found out where all those bottles ended up-they could enter all that data in to a computer and make a pretty detailed model to... to show where the currents go.
W: In fact, they did. And they also found a neat way to test that model. There was a freighter carrying sneakers from a factory in Asia. It was caught in a big storm and thousands of pairs of sneakers got dumped in the Pacific Ocean.
M: Really？ What a waste!
W: Yeah. Turns out, though, that hundreds of these shoes started washing up on beaches somewhere near Seattle, just about where the computer models had predicted the currents would carry them.
M: Gee. You mean all that stuff I find on the beaches might be part of some big scientific experiment？ I thought it was all just trash!
(20)
A．Collecting objects on the beach.
B．Creating computer models.
C．Mapping currents in the ocean.
D．Tracking water pollution.
第3题
M：But I heard from John that you got to see the film anyway.
Q：What did the woman do that night？
(14)
A．Drived in the wind and rain.
B．Listened to John's explanation.
C．Went to an indoor theater.
D．Saw a film that is wonderful.
第4题
M: That's not exactly true. It's true that deep down on the ocean floor we won't have the same kinds of currents we find in shallower parts. But we do find what we call turbidity currents. This wasn't in the book but the term came up in class. Do you remember what it means？
W: Umh, turbidity currents？ Oh, yeah! Isn't that when sediment like sand or mud gets stirred up and mixes with water and then this mixer kind of flows through the water around it, right？
M: Good!
W: Umh, but I thought that only happened in rivers.
M: Well, yes. This does occur in rivers, but we see turbidity currents deep in the ocean as well.
W: But how do they get started there？
M: Earthquakes mostly, when an earthquake occurs under water, it throws up tremendous, amounts of mud or sand that becomes suspended in a layer of water near the bottom of the ocean. This layer is so much denser and heavier than other ocean water that it flows right down the slopes o f the ocean floor and gains more and more speed as it moves along. Then it's just like the winds blowing across the desert picking up sand from one place and moving it along and finally dropping it somewhere else.
(23)
A．Earthquake.
B．Turbidity currents.
C．Erosion and the deposit of sediment on the deep sea floor.
D．Waves or currents that deep in the ocean.
第5题
A、stop at
B、turn right o
C、go to
D、ask at
第6题
How Wind Energy Works
Harnessing the wind is one of the cleanest, most sustainable ways to generate electricity. Wind power produces no toxic emissions and none of the heat trapping emissions that contribute to global warming. This, and the fact that wind power is one of the most abundant and increasingly cost-competitive energy resources, makes it a viable alternative to the fossil fuels that harm our health and threaten the environment.
The History of Wind Power
Wind power is both old and new. From the sailing ships of the ancient Greeks, to the grain mills of pre-industrial Holland, to the latest high-tech wind turbines rising over the Minnesota prairie, humans have used the power of the wind for thousands of years.
In the United States, the original heyday of wind was between 1870 and 1930, when thousands of farmers across the country used wind to pump water. Small electric wind turbines (叶轮机) were used in rural areas as far back as the 1920s, and prototypes of larger machines were built in the 1940s. When the New Deal brought grid-connected electricity to the countryside, however, windmills lost out.
Interest in wind power was reborn during the energy crises of the 1970s. Research by the U.S. Department of Energy (DOE) in the 1970s focused on large turbine designs. While these 2- and 3-MW machines proved mostly unsuccessful at the time, they did provide basic research on blade design and engineering principles. In the early 1990s, improvements in technology resulting in increased turbine reliability and lower costs of production provided another boost for wind development.
In other parts of the world, particularly in Europe, wind has had more consistent, long-term support. As a result, European countries are currently capable of meeting more of their electricity demands through wind power. Denmark, for example, already meets about 20 percent of its electricity demand from wind power. Wind generation also accounts for about six percent of the national power needs in Spain, and five percent in Germany. Serious commitments to reducing global warming emissions, local development, and the determination to avoid fuel imports have been the primary drivers of wind power development in Europe.
The Wind Resource
The wind resource how fast it blows, how often, and when plays a significant role in its power generation cost. The power output from a wind turbine rises as a cube of wind speed. In other words, if wind speed doubles, the power output increases eight times. Therefore, higherspeed winds are more easily and inexpensively captured.
Wind speeds are divided into seven classes with class one being the lowest, and class seven being the highest. A wind resource assessment evaluates the average wind speeds above a section of land (usually 50 meters high), and assigns that area a wind class. Wind turbines operate over a limited range of wind speeds. If the wind is too slow, they won't be able to turn, and if too fast, they shut down to avoid being damaged. Wind speeds in classes three (6.7 - 7.4 meters per second (m/s)) and above are typically needed to economically generate power. Ideally, a wind turbine should be matched to the speed and frequency of the resource to maximize power production.
Several factors can affect wind speed, and the ability of a turbine to generate more power. For example, wind speed increases as the height from the ground increases. If wind speed at 10 meters off the ground is 6 m/s, it will be about 7.5 m/s at a height of 50 meters. The rotors (旋翼) of the newest wind turbines can now reach heights up to 70 meters. In addition to height, the power in the wind varies with temperature and altitude, both of which affect the air density.
The more the wind blows, the more power will be produced by wind turbines. But, of course, the wind does not blow consistently all the
A．Y
B．N
C．NG
第7题
A．Convince the man that they should rest for a while.
B．Teach the man about the types of clouds.
C．Entertain the man with some interesting weather stories.
D．Persuade the man to turn around and go down the hill.
第8题
Types of Climate
Climate is the combination of temperature, moisture, wind, and sunshine at a place over a period of many years. Weather is made up of atmospheric conditions during a few hours or days. The weather may be rainy on a certain day. But that place may usually have a warm, dry, sunny climate. We learn about the climate of a place by studying its temperature, moisture, wind, and sunshine from season to season and year to year.
Temperature and the amount of rainfall are the two most important elements of climate. Others are humidity (air moisture), cloudiness, fog, sunshine, wind, storms, and air pressure.
There are many different types of climate on earth. Climates of the world can be classified according to their latitudes and the plants that grow there. Different kinds of plants need different amounts of heat and moisture for growth. The vegetation of a region tells us about temperature and rainfall conditions over a long period of time.
Tropical Climates
Tropical climates are found in regions between 35N and 35S latitude. In the tropical rain forest (nearest the equator) conditions are warm and rainy all year long, and there is a thick cover of trees. Places farther north and south of the equator have a tropical wet-and-dry climate. There the forests are not so dense, and many trees lose their leaves in the dry season. Along 23.5N and 23.5S latitude there are vast regions of tropical desert climate, where very little vegetation can grow.
Subtropical Climates
Subtropical climates are usually found between 30 and 40 North and South latitudes. The subtropical western coasts of the continents have a Mediterranean climate. Summers are hot and dry; winters are mild and wet. On the subtropical eastern coasts of continents the climate is humid subtropical. Summers are hot, and winters are mild. There is enough rainfall in all seasons for forests.
Mid-latitude Climate
Mid-latitude climates occur between 40 and 60 NS latitudes. Strong westerly winds blow in the mid-latitudes. The climate of the west coast of North America is mild and rainy most of the year. It helps the growth of fine timber forests. Some places in the mid-latitudes do not receive moisture because of mountain barriers or their great distances from the oceans. Humid continental climates cover large mid-latitude area in eastern parts of the continents. They are forest climates with cold winters and warm summers. Most of the rainfall comes in the summer.
High-latitude Climates
High-latitude climates occur from 60 to the poles, North and South. In the high latitudes it is very cold in winter and cool in summer. The short summers are warm enough for forests of evergreen trees. Greenland and Antarctica have a polar climate, where great ice caps exist because of year-round freezing.
High-altitude Climates
Highland climates are cooler than the surrounding lowlands because of the effects of altitude. Highland climates are found on the high mountains of the world, even on the equator. In the tropics and mid-latitudes different kinds of vegetation grow in zones up the slopes of mountains to the permanent snowfields.
The Causes of Different Climates
The differences in the climate from place to place are caused by climate controls. The major climate controls are latitude, altitude, land and water bodies, ocean currents, and storm centers.
Latitudes make climates colder toward the north and south poles (high latitudes) than at the tropics near the equator (low altitudes). Low-latitude regions remain warm throughout the year. At higher latitudes there are greater differences between winter and summer temperatures.
Altitude affects climate by lowering temperatures as the height above sea level increases. At high altitudes the air is less dense and does not absorb and hold as much heat. On the average, the temperature drops about 2 degrees Celsius
A．Y
B．N
C．NG
第9题
Types of Climate
Climate is the combination of temperature, moisture, wind, and sunshine at a place over a period of many years. Weather is made up of atmospheric conditions during a few hours or days. The weather may be rainy on a certain day. But that place may usually have a warm, dry, sunny climate. We learn about the climate of a place by studying its temperature, moistare, wind, and sunshine from season to season and year to year.
Temperature and the amount of rainfall are the two most important elements of climate. Others are humidity(air moisture), cloudiness, fog, sunshine, wind, storms, and air pressure.
There are many different types of climate on earth. Climates of the world can be classified according to their latitudes and the plants that grow there. Different kinds of plants need different amounts of heat and moisture for growth. The vegetation of a region tells us about temperature and rainfall conditions over a long period of time.
Tropical Climates
Tropical climates are found in regions between 35 N and 35 S latitude. In the tropical rain forest(nearest the equator)conditions are warm and rainy all year long, and there is a thick cover of trees. Places farther north and south of the equator have a tropical wet-and-try climate. There the forests are not so dense, and many trees lose their leaves in the dry season. Along 23.5 N and 23.5 S latitude there are vast regions of tropical desert climate, where very little vegetation can grow.
Subtropical Climates
Subtropical climates are usually found between 30 and 40 North and South latitudes. The subtropical western coasts of the continents have a Mediterranean climate. Summers are hot and dry; winters are mild and wet. On the subtropical eastern coasts of continents the climate is humid subtropical. Summers are hot, and winters are mild. There is enough rainfall in all seasons for forests.
Mid-latitude Climates
Mid-latitude climates occur between 40 and 60 NS latitudes. Strong westerly winds blow in the mid latitudes. The climate of the west coast of North America is mild and rainy most of the year. It helps the growth of fine timber forests. Some places in the mid-latitudes do not receive moisture because of mountain barriers or their great distance from the oceans. Humid continental climates cover large mid-latitude areas in eastern parts of the continents. They are forest climates with cold winters and warm summers. Most of the rainfall comes in the summer.
High-latitude Climates
High-latitude climates occur from 60 to the poles, North and South. In the high latitudes temperatures are very cold in winter and cool in summer. The short summers are warm enough for forests of ever green trees. Greenland and Antarctica have a polar climate, where great ice caps exist because of year round freezing.
High-altitude Climates
Highland climates are cooler than the surrounding lowlands because of the effects of altitude. High land climates are found on the high mountains of the world, even on the equator. In the tropics and mid latitudes different kinds of vegetation grow in zones up the slopes of mountains to the permanent snow fields.
The Causes of Different Climates
The differences in climate from place to place are caused by climatic controls. The major climatic controls are latitude, altitude, land and water bodies, ocean currents, winds, and storm centers.
Latitude makes climates colder toward the north and south poles(high latitudes)than at the tropics near the equator(low latitudes). Low-latitude regions remain warm throughout the year. At higher latitudes there are greater differences between winter and summer temperatures.
Altitude affects climate by lowering temperatures as the height above sea level increases. At high altitudes the air is less dense and does not absorb and hold as
A．Y
B．N
C．NG
第10题
Finding the resources to meet this demand in a 【S2】________, sustainable way is the cornerstone of our nation’s energy security, and will be one of the major 【S3】________ of the 21st century. Alternative forms of energy --- bio-fuels, wind and solar, to name a few --- are 【S4】________ being funded and developed, and will play a growing 【S5】________ in the world’s energy supply. But experts say that, even when 【S6】________, alternative energy sources will likely meet only about 30% of the world’s energy needs by 2050.
For example, even with 【S7】________ investments, such as the $93 million for wind energy development 【S8】________ in the American Recovery and Reinvestment Act, important alternative energy sources such as wind and bio-fuels 【S9】________ only about 1% of the market today. Energy and sustainability experts say the answer to our future energy needs will likely come from a lot of 【S10】________ --- both traditional and alternative.
A stable B solutions C significant D role E progress
F marvelous G included H growth I exactly J consist
K comprise L competitions M combined N challenges O certainly
【S1】
【S2】
【S3】
【S4】
【S5】
【S6】
【S7】
【S8】
【S9】
【S10】
请帮忙给出每个问题的正确答案和分析，谢谢！
