阅读理解 Metals usually occur in nature as minerals. At present, about 80 different metals are known to man. But with so many metals to choose from the question arises: which metal shall we use? Is there 题目和参考答案——青夏教育精英家教网—

阅读理解

　　Metals usually occur (发生,出现) in nature as minerals(矿石). At present, about 80 different metals are known to man. But with so many metals to choose from the question arises: which metal shall we use? Is there any metal that is “best for everything”? Of course not. For example, iron is strong but it rusts easily, while gold, one of the first metals found by man, does not rust at all. Should we use gold, therefore, to build fences? Imagine the cost of a fence made of gold! It’s important to consider the cost and the supply (提供)of a metal. Also, when we choose a metal for a certain job, we examine its physical properties. Is it strong enough to be used as a support for a bridge? Can it he used in a telephone to conduct (传导) electncity? Is it light enough to be used in an air plane wing? Can it he drawn out to make a fine wire? We also examine its chemical properties. Will it resist acid (酸) ? Is it too active to use? Is it easy to combine [ (使)结合] with other elements? Each use must be studied carefully. Then we can choose the right kind of metal, or combinations(结合)of metals.

　　The metals used for constructing buildings, cars, planes and ships must he strong and easy to form by casing, machining, and cutting. These metals are called structural(生锈)metals. The two most important structural (结构的) metals are iron (steel) and aluminum. Aluminum, which is much lighter than iron, has made possible the modem aviation (航空) industry.

　　Very few of the metal things we use in industry and every day life are made of a single pure metal. Most of them are combinations of metals called alloys (合金). Alloys are formed when two or more metals are melted together and allowed to cool and harden. It has been known for a long time that when some metals are combined in this way, the alloy takes on new physical properties (性质). The use of alloy makes it possible to manufacture (制造) many articles which must have special properties. Nowadays, if an inventor cannot find a metal that suits his purpose, he tries to have a new alloy made that will. The search for new alloys is going on all the time.

1．Metals are usually ________.

[　　]

A．best for everything

B．made use of in daily life in pure forms

C．found in nature as minerals

D．in the same quality

2．________ According to the text, uses of metals depend on their ________.

[　　]

A．costs

B．supplies

C．properties

D．all of the above

3．The properties most important to a structural are its ________.

[　　]

A．lightness and activity

B．electric conductivity and heat conductivity

C．strength and easiness of shaping

D．resistance to acids and capability of being bent

4．A combination of two or more metals is called ________.

[　　]

A．casting

B．alloying

C．melting

D．machining

5．The characteristic of alloy is ________.

[　　]

A．new chemical properties

B．new physical properties

C．special ways of formation

D．rarity

答案：C;D;C;B;B

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阅读理解

A Giant Leap for China

　　A few days ago, he was just Colonel(上校)Yang; few people knew his name or recognized his face．But last Thursday, when he came back to the earth after a 21-hour trip to space, Yang Liwei’s smile was seen across the world above the magic words：“China’s first spaceman”．

　　The 38-year-old astronaut was sent into space at 9 a. m．Last Wednesday by China’s Shenzhou Ⅴ spacecraft, which orbited the earth 14 times．He landed safely at 6∶23 a. m．The next day, making China the third country successfully send a person into space, after the former Soviet Union and the US．

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　　While in space, Yang recorded everything he saw as well as showing China’s national flag and the United Nations’ flag to the people watching on TV at home．He also ate a meal of diced chicken and fried rice, before taking a 3-hour nap．The whole project went according to plan, but space exploration is not as easy as it seems．

　　Anyone who saw the destruction of the US space shuttle Columbia in February this year will know that Yang took a great risk．

　　He experienced extremely high temperatures, while the gravitation(重力)on take-off and landing were strong enough to force tears from his eyes．

　　He has spent five years training to become a spaceman．

　　“I eat all of my meals at the space programme’s dinning room and have never been able to take my son to kindergarten, ”he said．“I’ve never met his teachers．”

　　But becoming China’s first spaceman has made all the effort worthwhile．

　　“When I boarded the spacecraft for the first time, I couldn’t help feeling excited,” he said．“I decided that I had to fly it．”

　　To Chinese people, Yang is now a hero．One visitor to a Xinhua news agency online forum(网上论坛)said, “Yang’s trip is a giant leap forward for China．”

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(1)

What is the main idea of the story?
[　　]
A．	China’s first manned flight．
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D．	How Yang Liwei became China’s first spaceman．

(2)

How long did each of Yang’s orbits take on average?
[　　]
A．	1 hour．
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(3)

Why did the writer mention the gravitation forces on take-off and landing?
[　　]
A．	Because it was the most dangerous part of the space flight．
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(4)

Why did the writer use “giant leap” in the title?
[　　]
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(5)

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[　　]
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阅读理解

　　We all know what it is like to be unable to turn your head because of a cold in the muscles of your neck, or because an unexpected twist has made your neck ache and stiff．Your whole body feels tight．The slightest move makes you jump with pain．Nothing could be worse than a pain in the neck．

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(1)

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(2)

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(3)

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[　　]
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[　　]
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阅读理解

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阅读理解

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[　　]
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[　　]
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(3)

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[　　]
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阅读理解

　　Our house was directly across the street from the clinic entrance of John Hopkins Hospital in Baltimore．We lived downstairs and rented the upstairs rooms to out-patients at the clinic．

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(1)

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[　　]
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[　　]
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[　　]
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[　　]
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(5)

What might be the best title of the passage?
[　　]
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