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更多“［A］ snow ［B］ earth ［C］ room ［D…”相关的问题
Which of the following is true according to the passage？
A．The volume of the atmosphere is four times that of the world's.
B．The water in the oceans is the main source of rain and snow on land areas.
C．The atmosphere is mainly composed of the vapor carded over land by air currents.
D．The earth cannot support the water in the atmosphere if it falls down onto the earth suddenly.
Today, (6)_____, the potential problem is too much carbon dioxide. Could the increase in carbon dioxide (7)_____ a global rise in average temperature, and could such a rise have serious (8)_____ for human society？ Mathematical models that allow us to calculate the rise in temperature as a function of the increase (9)_____; that the (10)_____ is probably yes.
One mathematical model (11)_____ that doubling the atmospheric carbon dioxide would raise the global mean surface temperature by 2.5℃. This model assumes that the atmosphere's relative humidity remains constant and the temperature decreases with altitude at a (12)_____ of 6.5℃ per kilometer. The assumption of constant relative humidity is important, because water vapor in the atmosphere is another (13)_____ absorber or radiation at infrared wavelengths. Because warm air can hold more (14)_____ than cool air, the relative humidity will be constant (15)_____ the amount of water vapor in the atmosphere increases (16)_____ the temperature rises. (17)_____, more infrared radiation would be absorbed and reradiated (18)_____ to the Earth's surface. The resultant warming at the surface could be expected to melt snow and ice, (19)_____ the Earth's reflectivity. More solar radiation would be absorbed, (20)_____ to a further increase in temperature.
A．Whereas
B．If
C．Although
D．Because
Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft(束) of sunlight. To the casual observer, dust seems to act in a totally random fashion, moving about wildly without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2,500 inch in diameter. (78)It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it does not fall out of moving air at all. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall form. the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain.
What is the main topic of the passage？
A．The mechanics of rain.
B．The climate of North America.
C．How gravity affects air current.
D．Types of clouds.
The basic source of most water vapor is the ocean, evaporation, vapor transport, and precipitation (陈雨) make up the continuous movement of water from ocean to atmosphere to land and back to the sea. Rivers return water the sea. In an underground arc (弧) of the cycle, flowing bodies of water discharge some water directly into rivers and some directly to the sea.
What might have been discussed before this passage？
A．The ocean.
B．The earth.
C．The rainfall.
D．The atmosphere.
Scientists have found that the cause of this strange weather is that the air circulation pattern has changed and is now more variable than earlier in the twentieth century. This means that different regions of the world get long spells (持续时间) of the same type of weather, whether hot , cold, wet or windy.
However, weather experts have different views about why this has happened. One theory is that the temperature of the sea has increased. Another is that man’s activities on earth have disturbed the balance of nature.
Whatever the cause, the economics of many countries in the world depend upon the weather. And until we know exactly what effect man’s activities are having on the weather, we cannot make changes which might help. So for the moment the only answer is …wait and see!
26. Which of the following statements is TRUE according to the first paragraph？
A. We have never predicted the weather.
B. Man is now able to control the weather.
C. Strange weather has appeared only in some North American countries.
D. It has always been impossible for man to predict the weather accurately.
27. The strange weather patterns on the earth can he best described as ________.
A. steady and balanced C. likely to cause serious disasters
B. changeable but predictable D. unpredictable but favorable to man
28. The word “affecting” in Paragraph 1 can be replaced by ________.
A. yielding good crops in C. causing few losses in
B. having harmful effects on D. producing desired effects on
29. We can learn from Paragraph 2 that ________.
A. weather patterns are similar in different regions of the world
B. the air circulation pattern remains unchanged in the last century
C. our weather depends on the changes in the air circulation pattern
D. it is possible to predict weather patterns over a long period of time
30. It can be learned from this passage that ________.
A. scientists have similar opinions about the changing weather
B. no one is sure about the cause of the changing weather
C. cutting down forests has affected the climate
D. the weather will become worse in the future
Temperatures at Hudson Bay have risen by one half degree Fahrenheit every decade since 1950. Winter ice on the bay melts three weeks earlier than it did just 25 years ago, which means three fewer weeks of polar bear mealtime. Result: Polar bears are 10 percent thinner and produce 10 percent fewer cubs than they did 20 years ago. And though climatologists hotly debate the causes behind Earth's Arctic meltdown, "these changes are startling and unexpected,' says James McCarthy, co-leader of the United Nations Intergovernmental Panel on Climate Change.
The plight of polar bears is just the tip to the iceberg when it comes to mounting evidence of global warming. "There's definitely a stark contrast with the way things were at the start of the 20th century," says atmospheric scientist Leonard Druyan, of Columbia University. Recent data show the volume of Arctic sea ice has shrunk 20 percent since the 1950s; glaciers around the world are melting at rapidly increasing rates. Rivers and lakes in North America, Asia, and Europe now freeze about nine days later and thaw 10 days earlier than they did a century ago.
Most scientists believe the only effective strategy to halt global warming is to drastically reduce emissions of powerful air pollutants like carbon dioxide, which accounts for two-thirds of all greenhouse gases. In the last 150 years, the surging use of fossil fuels coal, oil, and natural gas -- has released 270 billion tons of carbon into the air in the form. of carbon dioxide. Fortunately, oceans, plants, and soils absorb more than half of all atmospheric carbon dioxide -- without them world temperatures might have already soared at an alarming rate.
By saying "Spring is usually prime food time for 1,200 polar bears"？ (Line I, Para. 1), the author means that ______.
A．spring is usually a good time for polar bears to carry out their mating rituals
B．the polar bears usually eat a lot in the spring
C．spring is generally a good time to hunt polar bears
D．polar bears usually hibernate in the spring
