第2部分 閱讀判斷

Eastern Quakes Can Trigger Big Shakes

In the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes. The largest, a magnitude（量）5.6 quake, shook thousands of fans in a college football stadium, caused cracks in a few buildings and scared many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes. If you watch the news on TV, you see reports about all sorts of natural disasters. But the most dangerous type of natural disaster, and also the most unpredictable, is the earthquake.

Researchers at the US Geological Survey（USGS）estimate that several million earthquakes occur globally each year. That may sound scary, but people don't feel many of them because they happen in remote and unpopulated regions. Many quakes happen under the ocean, and others have a very small magnitude.

Scientists know about small, remote quakes only because of very sensitive electronic devices called seismometers（地震儀）. These devices detect and measure the size of ground vibrations（震顫）produced by earthquakes. Altogether, USGS researchers use seismometers to identify and locate about 20000 earthquakes each year.

Although earthquakes can happen anywhere in the world, really big quakes occur only in certain areas. The largest ones register a magnitude 8 or higher and happen, on average, only once each year. Such big ones typically occur along the edges of Earth's tectonic plates（構(gòu)造板塊）.

Thctonic plates are huge pieces of Earth's crust（外殼）, sometimes many kilometers thick. Often, edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes occur. On average, tectonic plates move very slowly--bout the same speed as your fingernails grow.

But sometimes earthquakes rumble（轟轟作響）through portions of the landscape far from a plate's edges. Although less expected, these "mid-plate" small earthquakes can be stantial damage. Some of the biggest known examples hit the eastern half of the United States two centuries ago. Today, scientists are still puzzling over why the quakes occurred and when similar ones might occur.

16. Oklahoma is an area often experiencing natural disasters.

A. Right B.Wrong C. Not mentioned

17. The earthquake is the most unpredictable natural disaster.

A. Right B.Wrong C. Not mentioned

18. Few earthquakes happen without people's awareness.

A. Right B.Wrong C. Not mentioned

19. Seismometers can identify and locate most of the earthquakes in China.

A. Right B.Wrong C. Not mentioned

20. Big earthquakes of a magnitude 8 or higher seldom happen far from the edges of tectonic plates.

A. Right B.Wrong C. Not mentioned

21. Whenever tectonic plates move, earthquakes happen.

A. Right B.Wrong C. Not mentioned

22. The earthquake that hit the eastern half of the United States two centuries ago is the biggest"mid-plate" one in history.

A. Right B.Wrong C. Not mentioned

16 A  根據(jù)第一段倒數(shù)第二句：If you watch the news on TV, you see reports about all sorts of natural disasters．（如果你經(jīng)?？措娨暤脑?，你會看到各種各樣的關(guān)于自然災(zāi)害的報道。）

17 A  根據(jù)第一段最后一句：But the most dangerous type of natural disaster, and also the most unpredictable, is the earthquake.

18 B  本題的意思是：幾乎所有的地震人們都有感知。根據(jù)第二段最后兩句，我們得出：很多地震是人們感覺不到的。

19 C  本文根本沒有提到中國。

20 A  根據(jù)第四段最后一句：8級或8級以上的大地震一般發(fā)生在地球構(gòu)造板塊的邊緣。

21 B  根據(jù)第五段第三句：只有當?shù)厍虻陌鍓K互相摩擦?xí)r，地震才會發(fā)生。本句的意思是：    只要地球的板塊一挪動，地震就會發(fā)生。

22 C  根據(jù)本文倒數(shù)第二句：Some of the biggest known example...（一些已知的在美國東半部發(fā)生的地震是最大的例子），但沒有說明是歷史上最大的地震。

（責任編輯：vstara）

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