2018职称英语模拟题：理工类4

>>职称英语理工类模拟试题：2018职称英语模拟题：理工类4

>>职称英语考试理工类备考课程

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.

单选题第1题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

参考答案：A

单选题第2题The ground beneath our feet is indeed still.

A.Right

B.Wrong

C.Not mentioned

参考答案：B

单选题第3题The shape of lands and oceans are slowly changed with the movements of plates.

A.Right

B.Wrong

C.Not mentioned

参考答案：A

单选题第4题Earth cooled down shortly after it was formed.

A.Right

B.Wrong

C.Not mentioned

参考答案：C

单选题第5题Scientists once estimated that Earth's crust started shifting three billion years ago.

A.Right

B.Wrong

C.Not mentioned

参考答案：B

单选题第6题The lsua supracrustal belt is now a popular holiday resort.

A.Right

B.Wrong

C.Not mentioned

参考答案：C

单选题第7题It took a long time for the melted crust to become hard.

A.Right

B.Wrong

C.Not mentioned

参考答案：C

对于上面的职称英语模拟题大家要都理解掌握了吗，登录坦途网职称英语考试频道，为你提供更多职称英语理工类模拟试题，让你的备考复习之路更加有效。