上海运用非开挖技术的发展情况?

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问题:

上海运用非开挖技术的发展情况?

考点:机械工程顶管技术顶管技术题库
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Scientists have not come close to understanding all the different kinds of life on the planet, but US researcher Craig Venter is already working on creating the first artificial life.

Venter and his researchers made a breakthrough this August. They successfully moved the DNA of one type of bacteria(细菌) to a yeast(酵母) cell, changed it, then put it into another bacterial cell.

“Bacteria have systems that protect them from foreign DNA,” Venter explained to the BBC. In the experiment, the team managed to block this system.

The experiment was performed on a simple type of bacteria called Mycoplasma mycoides. The team took the bacteria’s genes and put them into a yeast cell.

Putting the DNA in a yeast cell allowed the team to change the genes----in this case, taking out a gene that was not necessary for the bacteria to live.

They then put the gene into a host bacteria cell. The cell went on to divide normally, producing new healthy bacteria.

In January, the team created artificial genes of a new type of bacteria. Their next goal is to put the artificial DNA into a host cell to create a new species, according to a report in Science magazine.

“If we don’t make any errors, I think it should work and we should have the first artificial species by the end of the year,” Venter said in the report.

The first artificial life from is likely to be a simple man-made bacteria, to prove that the technology can work. But that form will be followed by more complex bacteria that turn coal into cleaner natural gas, or algae that can take in carbon dioxide and change it into fuel.

Many scientists think it’s good news to have this artificial life, but others are worried that the technology to create new organisms might end up in the wrong hands, with dangerous results.

小题1:Craig Venter and his team are working to ______.

A.create a new animal

B.clone a new species

C.produce the first artificial bacteria

D.develop a new system小题2:Which of the following is the right order of the experiment?

a. A gene was removed and put into a host bacteria cell.

b. The genes were put into a yeast cell.

c. The cell produced new healthy bacteria.

d. The genes were changed.

e. Some genes were taken out of Mycoplasma mycoides.

A.d-e-a-c-b

B.e-b-d-a-c

C.a-d-e-c-b

D.b-e-d-c-a小题3:According to the passage, complex artificial bacteria, which will follow the first simple man-made bacteria, are intended to ______.

A.cure deadly diseases

B.prepare the Earth for natural disasters

C.prove that the technology can work

D.improve the earth’s environment小题4:We can learn from the passage that ______.

A.Venter and his team are the only scientists trying to create artificial life

B.The experiment was based on research into different kinds of life on Earth

C.A new type of bacteria was created in January

D.All scientists are not in favor of the research

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肛窦炎中医辨证为湿热下注,方选()

A.萆薜渗湿汤

B.龙胆泻肝汤

C.导赤散

D.半夏泻心汤

E.滋水清肝饮

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物体克服重力做5J的功,则它的重力势能增加了(  )

A.5J

B.-5J

C.0

D.不能确定

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欲表示末端无确定数据的资料平均水平时,宜采用的指标是()

A.算术均数

B.几何均数

C.中位数

D.众数

E.算术均数和中位数

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