学位英语

第2部分：阅读判断(第16～22题，每题1分，共7分)

下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。

Earth Rocks On

Most of the time, the ground feels solid beneath our feet. That's comforting. But it's also misleading because there's actually a lot going on underground. Masses of land (called plates) slip, slide, and bump against each other, slowly changing the shape of continents and oceans over millions and billions of years.

Scientists know that Earth formed about 4.5 billion years ago. They also know that our planet was hot at first. As it cooled, its outermost layer, called the crust, eventually formed moving plates. Exactly when this shift happened, however, is an open question.

Now, an international group of researchers has an answer. They've found new evidence suggesting that Earth's crust (地壳) started shifting at least 3.8 billion years ago. The new estimate is 1.3 billion years earlier than previous ones.

Not long before 3.8 billion years ago, lots of asteroids (小行星) were pummeling Earth, keeping its crust in a hot, molten state. After the hard crust formed, much of it sank at various times into the planet's hot insides. There, it melted before returning to the surface as lava.

In some places, however, the crust never sank. One of the oldest such places is in Greenland, in an area called the Isua supracrustal(上地壳) belt. The rocky crust there is between 3.7 and 3.8 billion years old. The belt was once part of the seafloor, but now it is exposed to air.

The researchers recently look at the Isua supracrustal belt. They noticed long, parallel cracks in the rock that have been filled in with a type of volcanic rock.

To explain this structure, the scientists propose that tension in the crust caused the seafloor to crack open long ago. Hot, liquid rock, called magma(岩浆), flowed up slowly from deep inside Earth to fill the cracks. Finally, the area cooled, forming what we see today.

That explanation, plus chemical clues inside the rock, suggests that the Isua supracrustal belt was once part of a plate under the ocean, beginning around 3.8 billion years ago.

16 The ground beneath our feet is indeed still.

A Right

B Wrong

C Not mentioned

17 The shape of lands and oceans are slowly changed with the movements of plates.

A Right

B Wrong

C Not mentioned

18 Earth cooled down shortly after it was formed.

A Right

B Wrong

C Not mentioned

19 Scientists once estimated that Earth's crust started shifting three billion years ago.

A Right

B Wrong

C Not mentioned

20.It took a long time for the melted crust to become hard.

A Right

B Wrong

C Not mentioned

21.The formation of the Isua supracrustal belt is thought to have started about 3.8 billion years ago.

A Right

B Wrong

C Not mentioned

22. The lsua supracrustal belt is now a popular holiday resort.

A Right

B Wrong

C Not mentioned

16 B 本文第一段提到 "尽管我们感觉脚下的大地在大多数的时候是实心固体的，但实际上地下的物质一直在运动，这种运动慢慢改变着大陆和海洋的形状"。提干认为"我们脚 下的地球是静止的"不符合文意，所以选择 B。

17 A 本文第一段提到"随着板块的滑动和互相碰撞，大陆和海洋在慢慢改变着形状"。提干符合文章本意，所以选择 A。

18 C 文章第二段提到了地球这颗行星慢慢冷却后，它的地壳慢慢形成移动的板块，并没有提及地球在冷却后慢慢形成。题干的意思在文章中没有体现，所以选择 C。

19 B 文章第三段提到"他们发现的最新证据表明地壳的这种转变至少是发生在 38 亿年以前，这比之前的估计早了13 亿年"。也就是之前的估计应为 25 亿年前，题干"科学家曾 经估计地壳的转变发生在 30 亿年前"不符合题意，所以选择B。

20 C 文章第四段提到了 "坚硬的地亮形成之后……"，并没有提及这个过程的时间。题干表达的意思没有出现在文章中，所以选择C。

21 A 文章最后一句话提到"上地壳带开始形成于约3. 8 亿年前"，所以题干表达的意思是正确的，选择 A。

22 C 文章主题是研究者对地球的研究，并没有提到上地壳带是一个度假胜地。题干中的说法在文中没有提及，所以选择 C。

（责任编辑：vstara）

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