The velocity of the apparent wind can be more than the true wind，and come from the same direction，if certain conditions are present．One condition is that the ______．A.Ship's speed must be less than the true wind velocityB.True wind must be from dead aster

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第一篇

Renewable Energy Sources

Today petroleum（石油）provides around 40% of the world's energy needs, mostly
fuelling automobiles.Coal is still used,mostly in power stations,to cover one-quarter of our
energy needs,but it is the least efficient,unhealthiest and most environmentally damaging
fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves
of that will not last into the 22^nd century either. Most experts predict we will exhaust easily
accessible reserves within 50 years.Less-polluting renewable energy sources offer a more
practical long-term energy solution."Renewable"refers to the fact that these resources are
not used faster than they can be replaced.
Hydroelectric（水力发电的）power is now the most common form of renewable energy,
suDDIvina around 20%of world electricity.China's Three Gorges Dam is the largest ever.
At five times the size of the US's Hoover Dam, its 26 turbines（涡轮机）will generate the
equivalent energy of 18 coal-fired power stations.It will satisfy 3% of China's entire
electricity demand.
In 2003. the first commercial power station to use tidal（潮汐的）currents in the open
sea opened in Norway. It is designed like windmill（风车）,but others take the torm of
turbines.
As prices fall,wind power has become the fastest growing type of electricity
generation一quadrupling（翻两番）worldwide between 1999 and 2005. Modern wind farms
consist of turbines that generate electricity.Though it will be more expensive,there is more
than enoucih wind to provide the world's entire energy needs.Wind farms come in onshore
and offshore forms.They can often end up at spots of natural beauty,and are often
unpopular with residents.And turbines are not totally harmless一they can interfere with radar,
alter climate and kill sea birds.Scotland is building Europe's largest wind tarm,wnicn will
power 200.000 homes.The UK's goal is to generate one-fifth of power from renewable
sources,mainly wind,by 2020.But this may cause problems,because wind is unreiiable.

According to the passage,resources like wind are
A:renewable.
B:recyclable.
C:damaging.
D:scarce.

共用题干
Renewable Energy Sources
Today petroleum provides around 40%of the world's energy needs,mostly fuelling automobiles .Coal is still used,mostly in power stations,to cover one-quarter of our energy needs,but it is the least efficient,unhealthiest and most environmentally damaging fossil fuel.Natural gas reserves could plug some of the gap from oil,but reserves of that will not last into the 22nd century either.
Most experts predict we will exhaust easily accessible reserves within 50 years.We could fasi reach an energy crisis.We need to rapidly develop sustainable solutions to fuel our future.Lesspolluting renewable energy sources offer a more practical long-term energy solution.They may benefit the world's poor too."Renewable"refers to the fact that these resources are not used faster than they can be replaced.
The Chinese and Romans used watermills over 2,000 years ago. But the first hydroelectric dam was built in England in 1870.Hydroelectric power is now the most common form of renewable energy,supplying around 20%of world electricity. China's Three Gorges Dam,which has just been completed,is the largest ever. At five times the size of the US's Hoover Dam,its 26 turbines will generate the equivalent energy of 1 8 coal-fired power stations.It will satisfy 3%of China's entire electricity demand.Surprisingly,some argue that hydroelectric dams significantly contribute green- house gases.
In 2003,the first commercial power station to harness tidal currents in the open sea opened in Norway .It is designed like windmill,but others take the form of turbines.
As prices fall,wind power has become the fastest growing type of electricity generation-quadrupling worldwide between 1999 and 2005 .Modern wind farms consist of turbines that gener- ate electricity.Though it will be more expensive,there is more than enough wind to provide the world's entire energy needs. Wind farms come in onshore and offshore forms.They can often end up at spots of natural beauty,and are often unpopular with residents.And turbines are not totally benignthey can interfere with radar and leave a significant ecological footprint,altering climate and killing sea birds.Migrating birds may have more luck avoiding them.Scotland is building
Europe's largest wind farm,which will power 200,000 homes.The UK's goal is to generate one- fifth of power from renewable sources,mainly wind,by 2020 .But this may cause problems,be- cause wind is unreliable.

Which of the following statements is true of wind power?
A: There is plenty of wind to provide the world's entire energy needs.
B: It is the most rapidly growing type of electricity production.
C: It may not he reliable.
D: All of the above.

共用题干
第一篇

Renewable Energy Sources

Today petroleum（石油）provides around 40% of the world's energy needs, mostly
fuelling automobiles.Coal is still used,mostly in power stations,to cover one-quarter of our
energy needs,but it is the least efficient,unhealthiest and most environmentally damaging
fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves
of that will not last into the 22^nd century either. Most experts predict we will exhaust easily
accessible reserves within 50 years.Less-polluting renewable energy sources offer a more
practical long-term energy solution."Renewable"refers to the fact that these resources are
not used faster than they can be replaced.
Hydroelectric（水力发电的）power is now the most common form of renewable energy,
suDDIvina around 20%of world electricity.China's Three Gorges Dam is the largest ever.
At five times the size of the US's Hoover Dam, its 26 turbines（涡轮机）will generate the
equivalent energy of 18 coal-fired power stations.It will satisfy 3% of China's entire
electricity demand.
In 2003. the first commercial power station to use tidal（潮汐的）currents in the open
sea opened in Norway. It is designed like windmill（风车）,but others take the torm of
turbines.
As prices fall,wind power has become the fastest growing type of electricity
generation一quadrupling（翻两番）worldwide between 1999 and 2005. Modern wind farms
consist of turbines that generate electricity.Though it will be more expensive,there is more
than enoucih wind to provide the world's entire energy needs.Wind farms come in onshore
and offshore forms.They can often end up at spots of natural beauty,and are often
unpopular with residents.And turbines are not totally harmless一they can interfere with radar,
alter climate and kill sea birds.Scotland is building Europe's largest wind tarm,wnicn will
power 200.000 homes.The UK's goal is to generate one-fifth of power from renewable
sources,mainly wind,by 2020.But this may cause problems,because wind is unreiiable.

One of the problems with wind farms is that
A:there is not enough wind.
B:wind is not reliable.
C:they can only be built on the sea.
D:they might influence the world economy.

共用题干
Renewable Energy Sources
Today petroleum（石油）provides around 40% of the world's energy needs, mostly fuelling automobiles .Coal is still used,mostly in power stations,to cover one-quarter of our energy needs, but it is the least efficient, unhealthiest and most environmentally damaging fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years. Less-polluting renewable energy sources offer a more practical long-term energy solution. "Renewable"refers to the fact that these resources are not used faster than they can be replaced.
Hydroelectric（水力发电的）power is now the most common form of renewable energy , supplying around 20% of world electricity.China's Three Gorges Dam is the largest ever. At five times the size of the U. S. 's Hoover Dam,its 26 turbines (涡轮机）will generate the equivalent energy of 18 coal-fired power stations. It will satisfy 3%of China's entire electricity demand.
In 2003,the first commercial power station to use tidal（潮汐的）currents in the open sea opened in Norway. It is designed like windmill（风车）,but others take the form of turbines.
As prices fall,wind power has become the fastest growing type of electricity generation-quadrupling（翻两番）worldwide between 1 999 and 2005 . Modern wind farms consist of turbines that generate electricity. Though it will be more expensive,there is more than enough wind to provide the world's entire energy needs.Wind farms come in onshore and offshore forms. They can often end up at spots of natural beauty,and are often unpopular with residents. And turbines are not totally harmless-they can interfere with radar,alter climate and kill sea birds.Scotland is building Europe's largest wind farm,which will power 200 ,000 homes. The U.K. 's goal is to generate one-fifth of power from renewable sources,mainly wind,by 2020 .But this may cause problems, because wind is unreliable.

One of the problems with wind farms is that______.
A: there is not enough wind
B: wind is not reliable
C: they can only be built on the sea
D: they might influence the world economy