Pretoria, South Africa – Hundreds of swimmers play in the water along a South Africa beach. Suddenly a huge shark appears off shore and heads for the bathers. Before it can get close to the swimmers, 题目和参考答案——青夏教育精英家教网—

题目内容

Such a scene will soon become common along shark-in-fasted (鲨鱼成群的) shores. An electrical engineer from the University of Pretoria has developed an electrical system that repels (击退) sharks by controlling their movements. Confused by this action, the sharks end up turning away from the beach.

In this unusual shark-repellent method, an insulated (绝缘的) cable is buried on the bottom of the sea around a beach where people swim. When an electric current is sent through the cable, an electric field is produced in the water above the cable.

When shark swims into the electric field, nerve cells just below the shark' s skin will sense the field. The electricity produces a reflex (反射作用) action in the shark' s muscles, causing the dangerous animal to swim parallel to the cable. Confused by increasing loss of control of its muscles, the shark suddenly changes its direction and heads seaward, away from the electric field.

In a test of the invisible new shark-repellent system, a cable was placed around a beach in St. Lucia, an island around the beach a long time ago to keep sharks away from swimmers, and a net was left in place during the experiment.

When the electric field was left on for more than a year and a half, no sharks were found in the net. However, when the power was turned off,89 sharks ended up in the net.

Using the electric-wall method instead of net to protect bathers would avoid the needless death of many sharks, said biologists. Currently, thousands of sharks die each year when they become trapped in protective nets that surround holiday resorts in Africa and Australia. About 10 to 15 humans are killed by sharks annually.

1．Why doesn' t the shark attack the swimmers according to the passage?

A．Because there are so many swimmers in the water.

B．Because the shark isn’t so hungry as to eat the swimmers.

C．Because of some mysterious power from the heaven.

D．Because there is an invisible electric field confusing the shark.

2．An electrical engineer from the University of Pretoria has developed __ .

A．a protective net

B．a new shark-repellent system

C．the electric field

D．an insulated cable

3．An electric field is produced in the water above the cable .

A．only when a shark swims into the electric field

B．only when an insulated cable is buried on the bottom of the sea around a beach where people swim

C．only when an electric current is sent through the cable

D．only when the sharks are trapped in protective nets

4．Which of the following is NOT TRUE according to the passage?

A．Protective nets had been fixed earlier than the new shark-repellent system.

B．The new shark – repellent system will probably replace the protective nets.

C．Thousands of sharks have died each year since this new system was put into use.

D．Using the electric-wall instead of nets would avoid the needless death of many sharks.

【小题1】D

【小题2】B

【小题3】C

【小题4】C

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Pretoria, South Africa – Hundreds of swimmers play in the water along a South Africa beach. Suddenly a huge shark appears off shore and heads for the bathers. Before it can get close to the swimmers, the shark, for some mysterious reason, starts swimming parallel to the beach. Then it turns away from the shore and heads out to sea, leaving the swimmers untouched.
Such a scene will soon become common along shark-in-fasted (鲨鱼成群的) shores. An electrical engineer from the University of Pretoria has developed an electrical system that repels (击退) sharks by controlling their movements. Confused by this action, the sharks end up turning away from the beach.
In this unusual shark-repellent method, an insulated (绝缘的) cable is buried on the bottom of the sea around a beach where people swim. When an electric current is sent through the cable, an electric field is produced in the water above the cable.
When shark swims into the electric field, nerve cells just below the shark' s skin will sense the field. The electricity produces a reflex (反射作用) action in the shark' s muscles, causing the dangerous animal to swim parallel to the cable. Confused by increasing loss of control of its muscles, the shark suddenly changes its direction and heads seaward, away from the electric field.
In a test of the invisible new shark-repellent system, a cable was placed around a beach in St. Lucia, an island around the beach a long time ago to keep sharks away from swimmers, and a net was left in place during the experiment.
When the electric field was left on for more than a year and a half, no sharks were found in the net. However, when the power was turned off,89 sharks ended up in the net.
Using the electric-wall method instead of net to protect bathers would avoid the needless death of many sharks, said biologists. Currently, thousands of sharks die each year when they become trapped in protective nets that surround holiday resorts in Africa and Australia. About 10 to 15 humans are killed by sharks annually.
1．Why doesn' t the shark attack the swimmers according to the passage?
A．Because there are so many swimmers in the water.
B．Because the shark isn’t so hungry as to eat the swimmers.
C．Because of some mysterious power from the heaven.
D．Because there is an invisible electric field confusing the shark.
2．An electrical engineer from the University of Pretoria has developed __      .
A．a protective net
B．a new shark-repellent system
C．the electric field
D．an insulated cable
3．An electric field is produced in the water above the cable         .
A．only when a shark swims into the electric field
B．only when an insulated cable is buried on the bottom of the sea around a beach where people swim
C．only when an electric current is sent through the cable
D．only when the sharks are trapped in protective nets
4．Which of the following is NOT TRUE according to the passage?
A．Protective nets had been fixed earlier than the new shark-repellent system.
B．The new shark – repellent system will probably replace the protective nets.
C．Thousands of sharks have died each year since this new system was put into use.
D．Using the electric-wall instead of nets would avoid the needless death of many sharks.

When the electric field was left on for more than a year and a half, no sharks were found in the net. However, when the power was turned off,89 sharks ended up in the net.

1．Why doesn' t the shark attack the swimmers according to the passage?

A．Because there are so many swimmers in the water.

B．Because the shark isn’t so hungry as to eat the swimmers.

C．Because of some mysterious power from the heaven.

D．Because there is an invisible electric field confusing the shark.

2．An electrical engineer from the University of Pretoria has developed __ .

A．a protective net

B．a new shark-repellent system

C．the electric field

D．an insulated cable

3．An electric field is produced in the water above the cable .

A．only when a shark swims into the electric field

B．only when an insulated cable is buried on the bottom of the sea around a beach where people swim

C．only when an electric current is sent through the cable

D．only when the sharks are trapped in protective nets

4．Which of the following is NOT TRUE according to the passage?

A．Protective nets had been fixed earlier than the new shark-repellent system.

B．The new shark – repellent system will probably replace the protective nets.

C．Thousands of sharks have died each year since this new system was put into use.

D．Using the electric-wall instead of nets would avoid the needless death of many sharks.

Pretoria．South Africa—Hundreds 0f swimmers Play in the water along a South African beach．Suddenly a huge shark appears offshore and heads for the bathers．Before it can get close to the swimmers，the shark，for some mysterious reason，starts swimming parallel to the beach．Then it turns away from shore and heads out to sea，leaving the swimmers untouched．

Such a scene will soon become common along shark infested（鲨鱼出没）shores．An electrical engineer from the University of Pretoria has developed an electrical system that repels（击退）sharks by controlling their movements．Confused by this action，the sharks end up turning away from the beach．

In this unusual shark repellent method，an insulated（绝缘）cable is buried on the bottom of the sea around a beach from which people swim．When an electric current is sent though the cable，an electric field is produced in the water above the cable．

When the shark swims into the electric field，nerve cells just below the shark’s skin detect the field．The electricity produces a reflex（反射）action in the shark’s muscles，causing the dangerous animal with sharp teeth to swim parallel to the cable．Contused by increasing loss of control of its muscles，the shark suddenly changes its direction and heads seaward，away from the electric field．

In a test of the invisible new shark-repellent system，a cable was placed around a beach in St．Lucia an island in the tropics．A protective net，which had been installed around the beach a long time ago to keep sharks from swimmers，was left in place during the experiment．

When the electric field was 1eft on for more than a year and a half，no sharks were found in the nets．However,when the power was turned off，89 sharks ended up in the nets．

Using the electric wall method instead of nets to protect bathers would avoid the needless death of many sharks，say biologists．Currently，thousands of sharks die each year when they become trapped in protective nets that surround holiday resorts in Africa and Australia．About 10 to 15 humans are killed by sharks annually．

1.In the first passage，why doesn’t the shark attack the swimmers？

A．Because they are many swimmers in the water．

B．Because the shark doesn’t want to eat the swimmers。

C．Because of some mysterious reason from the God．

D．Because there is an invisible electric field confusing the shark．

2.An electrical engineer from the University of Pretoria has developed ．

A．A protective net B．A new shark-repellent system

C．The electric field D．An insulated cable

3.An electric field is produced in the water above the cable ．

A．only when the shark swims into the electric field

B．an insulated cable is buried on the bottom of the sea around a beach from which people

swim

C．only when an electric current is sent though the cable

D．only when the sharks are trapped in protective nets

4.Which of the following is NOT TRUE according to the passage?

A．Protective nets had been installed around the beach earlier than the new shark repellent system．

B．This new kind of shark repellent system wilt take place of the protective nets．

C．Thousands of sharks die and about 10 to 15 humans are killed by sharks each year in Africa and Australia since this new system was Put into use．

D．Using the electric wall method instead of nets to protect bathers would avoid the needless death of many sharks．

Tens of thousands of South Africans have joined dozens of world leaders for the national memorial service for former President Nelson Mandela. The service was held in front of a noisy crowd in the FNB stadium in Johannesburg.

US President Barack Obama said Mr Mandela was a "giant of history", describing him as the last great liberator of the 20th Century.The former South African president died last Thursday, aged 95.

The country is observing a series of commemorations（纪念） leading up to the funeral on Sunday. The memorial service, which began at about 12:00 (10:00 GMT), lasted about four hours. It was one of the biggest gatherings of international dignitaries（高层） in recent years, with more than 100 current（现任的） or former heads of state or government attending.

There had been fears people would be turned away. But with heavy rain, security and transport issues, and the fact that Tuesday was not declared a national holiday, areas of the 95,000-capacity stadium remained empty. Introducing the proceedings, the master of ceremonies, Cyril Ramaphosa, said that Mr Mandela's "long walk is over... and he can finally rest".

Current South African President Jacob Zuma made the keynote address but was booed （喝倒彩）in some parts of the ceremony. He said Mr Mandela was "one of a kind... a fearless freedom fighter who refused to allow the cruelty of the apartheid（种族隔离） state to stand in way of the struggle for the liberation of his people". Mr Zuma announced he was renaming the Union Buildings in Pretoria, where Mr Mandela will lie , as the Mandela Amphitheatre.

Earlier Mr Obama delivered his address, carried on the White House web site, to huge cheers. He said: "It is hard to eulogise（颂扬） any man... how much harder to do so for a giant of history, who moved a nation towards justice. "He said Nelson Mandela had taught the world the power of action and the power of ideas, and that it had taken a man like Mr Mandela to free not only the prisoner but also the jailer.

60. Why was the memorial service said to be one of the biggest gatherings of international dignities in recent years? .

A. Because large amounts of money had been spent.

B. Because everyone in the country had been asked to attend.

C. Because Nelson Mandela had taught the world the power of action .

D. Because more than 100 current or former heads of state or government attended it

61. The memorial service for Nelson Mandela took place .

A. on Sunday

B. on Tuesday

C. on Thursday

D. .on the day the passage doesn’t mention

62. When Mr. Obama said “It is hard to eulogise（颂扬） any man... how much harder to do so for a giant of history…”, he meant .

A. We don’t need to eulogise Nelson Mandela

B. It is much harder to eulogise Nelson Mandela

C. We shouldn’t eulogise Nelson Mandela in a hurry.

D. It is much easier to eulogise Nelson Mandela

63. It can be inferred that

A. Nelson Mandela only used the power of action to win his struggle.

B. Nelson Mandela paid much attention to the power of ideas to win his struggle.

C. Nelson Mandela used both the power of action and the power of ideas to win his struggle.

D. Nelson Mandela refused to use the power of ideas to win his struggle.

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