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老托福阅读No.173

[日期:04-08] 来源:网络  作者:未知 [字体: ]

老托福阅读No.173


2005.05

Questions 1-9

With the onset of the Industrial Revolution, knowing the age of rocks became a necessary prerequisite to finding industrial minerals, such as coal, iron, and the other materials that fueled and sustained the great Western industrialization of the eighteenth and nineteenth centuries. It was in the mining regions where engineers, who needed a better system for organizing the various types of rock scattered across Earth's surface, first grappled with scientific approaches to understanding the age of various rocks—and the age of Earth. They realized that if the various rock units could he dated by their relative ages, correlations among even widely separated rocks could be established and from this, some order recognized.

The pioneering European geologists first believed that identifying a rock's type would give them a strong clue to the age of the rock formation and that one of the most powerful clues came from the hardness of a given rock. Specific rock types were thus assumed to have formed at characteristically different rimes, the softest rocks having formed the most recently. This crude type of dating was first used to understand the way mountains were formed, In the mid-1700's it was thought that there were three distinct types of mountains in Europe, each formed by a different type of rock and each created at a different time. According to this theory, the oldest were the Alps, which had interior cores composed of very hard, crystalline rocks (such as granite, schist, or basalt). These mountains were called Primitive. Sitting on the flanks of the Primitive mountains were younger, smaller, Secondary mountains composed of layered sedimentary rocks such as limestone. They were often rich with fossils and intermediate in hardness. The youngest Tertiary mountains were composed of softer mudstones and sandstone. Rock type, hardness, and size thus established mountain type, and rock type also became a proxy for age. However, study soon exposed the fallacy of these early notions. It was discovered that some of the very high mountains were composed of the softest sediments and that even hard volcanic rock was sometimes found in very low mountains. By the early 1800's, it was understood that rock type was of no help in establishing age.

1, What does the passage mainly discuss? A

(A) An early attempt to find reliable rules for dating rocks and mountains

(B) The search for different rock types to be used in industry

(C) Changing views about what caused high mountain ranges to form

(D) A controversy about rocks between mining engineers and geologists

2. The word "grappled" in line 5 is closest in meaning to D

(A) competed

(B) struggled

(C) agreed

(D) searched

3. According to the passage, how could knowing the age of rocks benefit industry'? C

(A) It reduced the dependence of industry on coal.

(B) It helped miners find new types of minerals.

(C) It helped people in their search for industrial minerals.

(D) It made it possible to mine rocks under Earth's surface.

4. According to the passage, mining engineers were the first to realize that B

(A) various types of rock were scattered across Earth's surface

(B) rocks in different locations could be related by their age

(C) there were wide differences in the appearance of different types of rocks

(D) older rocks were better suited for industrial use

5. The word “They" in line 16 refers to D

(A) crystalline rocks

(B) the flanks

(C) the Primitive mountains

(D) layered sedimentary rocks

6. Why does the author mention rock type, hardness, and size in lines 18? D

(A) To describe the development of European geology

(B) To explain the differences between mudstone and sandstone

(C) To introduce the new theories that were about to emerge in the 1800's

(D) To summarize the characteristics thought to distinguish mountain types

7. According to the passage, pioneer geologists believed that to determine a rock's age, it was helpful to know D

(A) how deep under the surface the rock was located

(B) how much power was needed to remove the rock

(C) how rough the rock's texture was

(D) how soft the rock was

8. According to the passage, early geologists believed which of the following about Primitive mountains? C

(A) They had interior cores of sandstone and mudstone,

(B) They contained a large number of fossils.

(C) They had been formed during the same limited period in Earth's history.

(D)They were smaller than the Tertiary mountains.

9. The word "proxy" in line 19 is closest in meaning to D

(A) substitute

(B) preparation

(C) product

(D) choice

 

 

 

 

 

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