题目内容

The climate of earth has fluctuated quite a bit over the last 4.6 billion years of our planet’s history and it can be expected that the climate will continue to change. One of the most intriguing questions in earth science is whether the periods of ice ages are over or arc we living in an "interglacial" period of time between ice ages The geologic time period we are now living in is known as the Holocene (全新世). This epoch began about 11,000 years ago which was the end of the last glacial period and the end of the Pleistocene (更新世) epoch. The Pleistocene was an epoch of cool glacial and warmer interglacial periods which began about 1.8 million years ago. Since the glacial period known as the "Wisconsin" in North America and "Wrm’ in Europe when over 10 million square miles (about 27 million km2 ) of North America, Asia, and Europe were covered by ice, almost all of the ice sheets covering the land and glaciers in the mountains have retreated. Today, about ten percent of the earth’s surface is covered by ice; 96% of this ice is located in Antarctica and Greenland. Glacial ice is also present in such diverse places as Alaska, Canada, New Zealand, Asia, and California. As only 11,000 years has passed since the last Ice Age, scientists can not be certain that we are indeed living in a post- glacial Holocene epoch instead of an interglacial period of the Pleistocene and thus due for another ice age in the geologic future. Some scientists believe that an increase in global temperature, as we are now experiencing, could be a sign of an impending ice age and could actually increase the amount of ice on the earth’s surface. The cold, dry air above the Arctic and Antarctica carries little moisture and drops little snow on the regions. An increase in global temperature could increase the mount of moisture in the air and increase the amount of snowfall. After years of more snowfall than melting, the Polar Regions could accumulate more ice. An accumulation of ice would lead to a lowering of the level of the oceans and there would be further, unanticipated changes in the global climate system as well. Our short history on earth and our shorter record of the climate keeps us from fully understanding the implications of global warming. Without a doubt, an increase in the earth’s temperature will have major consequences for all life on this planet. What’s the result of an accumulation of ice

An accumulation of ice would make the global climate system altered.
B. An accumulation of ice would make snow more difficult to melt.
C. An accumulation of ice would increase the amount of moisture in the air.
D. An accumulation of ice would increase the global temperature.

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种群密度的变化影响种内竞争,使出生率、死亡率等种群参数变化,这样的种群调节方式是______。

林带可以使冬季的积雪免于被风吹走,因而保持了地温。( )

A. 对
B. 错

Section ADirections: This section is to test your ability to give proper answers to questions. There are 5 recorded questions in it. After each question, there is a pause. The questions will be spoken two times. When you hear a question, you should decide on the correct answer from the 4 choices marked A), B), C) and D) given in your test paper. Then you should mark the corresponding letter on the Answer Sheet with a single line through the centre.

A. No, I don’t.
B. Yes, please.
C. Beef, please.
D. I am eating.

法律由国家制定或认可,并由国家强制力保证实施的,反映着统治阶级意志的规范体系。( )

A. 对
B. 错

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