如何理解逆向工程和再工程?

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问题:

如何理解逆向工程和再工程?

考点:信息系统分析与设计信息系统分析与设计题库
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科学家P.Tatapudi等人首先使用在空气中电解水(酸性条件下)的方法在阳极制得臭氧,阴极制得过氧化氢。电解总方程式为:3H2O+3O2  3H2O2+O3,下列说法正确的是

A.电解产物在应用中都只能作为氧化剂

B.电解一段时间后,溶液pH不变

C.每生成1 mol O3转移电子数为3 mol

D.阳极的反应:3H2O→O3+6H+6e-

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目前,构成因特网的主干网的是( )。

A.ANSNET

B.NSFNET

C.CSNET

D.ARPANET

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下列有关基本表的说法,正确的是( )。

A.在数据库中,一个表打开后,另一个表将自动关闭

B.基本表中的字段名可以在设计视图或数据表视图中更改

C.在表的设计视图中可以通过删除列来删除一个字段

D.在表的数据表视图中可以对字段属性进行设置

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(2人人7•淮安)小明同学跟z爸爸参观车展.解说员介绍汽车性能时,总提到“发动机功率”、“发动机效率”等.请你用所学知识,简述“发动机功率”和“发动机效率”所表达的汽车发动机性能.

(1)发动机功率:______.

(2)发动机效率:______.

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Beijing had its biggest snowfall since 1951. Britain is suffering through its longest cold snap (寒潮) since 1981. And freezing weather is hitting the Deep South, including Florida’s orange groves and beaches.

Whatever happened to global warming?

Such weather doesn’t seem to fit with warnings from scientists that the Earth is warming because of greenhouse gases. But experts say the cold snap doesn’t contradict global warming at all—it’s just a temporary phenomenon in the long-term heating trend. “It’s part of natural variability,” said Gerald Meehl, a senior scientist. With global warming, he said, “we’ll still have record cold temperatures. We’ll just have fewer of them.”

Scientists say man-made climate change does have the potential to cause more frequent and more severe weather extremes. But experts did not connect the current cold snap to climate change.

So what is going on?

“We basically have seen just a big outbreak of Arctic air over populated areas of the Northern Hemisphere”, Arndt said.

In the atmosphere, large rivers of air travel roughly west to east around the globe between the Arctic and the tropics. This air flow acts like a fence to keep Arctic air restricted. But recently, this air flow has become bent into a zigzag (之字形) pattern, wandering north and south. If you live in a place where it brings air up from the south, you get warm weather. In fact, record highs were reported this week in Washington state and Alaska.

But in the eastern United States, like some other unlucky parts of the globe, Arctic air is coming from the north. And that’s how you get a temperature of 3 degrees in Beijing, a reading of minus-42 in mainland Norway, and 18 inches of snow in parts of Britain. The zigzag pattern arises naturally from time to time, but it is not clear why it’s so strong right now.

小题1:What is the best title of the text?

A.Freezing weather is hitting the Deep South.

B.We’ll still have record cold temperatures.

C.The air flow has become a zigzag pattern.

D.Cold snap doesn’t contradict global warming.小题2:With global warming, we will ______.

A.also meet with severe cold snap

B.have more hot temperatures forever

C.never experience cold temperatures

D.have more cold temperatures小题3:According to experts, the current cold snap ______.

A.suggests that the climate has changed greatly

B.is not related to the climate change

C.shows that the climate will turn cold

D.is affected by global warming小题4:Beijing had its biggest snowfall since 1951 because of ______.

A.a fence from the Arctic

B.a cooling trend in climate

C.a big outbreak of Arctic air

D.its large population小题5:We can conclude that ______.

A.not all the parts of the Northern Hemisphere are cold in face of the cold snap

B.the zigzag pattern arises naturally accidentally

C.Beijing will get cold weather next year

D.Washington state and Alaska will not face cold weather next year

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