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__________the sun is the central body of the solar system so the nucleus is the core of the atom．
A．When
B．If
C．Now that
D．Just as
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更多 “ __________the sun is the central body of the solar system so the nucleus is the core of the atom．A．WhenB．IfC．Now thatD．Just as ” 相关考题
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When people speak of solar energy, they only think of sun’s rays heating a home or ________ electricity from the sun.
A.deriveB.to deriveC.derivingD.of deriving.
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For what purpose are the diving pipes used?A. To absorb heat from the sun.B. To store heat for future use.C. To turn solar energy into heat energy.D. To carry heat down below the surface.
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It is stated in astrology that ________.[A] the sun is so distant from us that it was hard to follow its motion[B] the sun was moving westward around the sky[C] the motion of the sun is at the rate of about thirty degrees every week[D] the motion of the sun is similar to the revolution of the earth around the sun
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It was()to see the students' excitement when they discovered that simple materials could be used to cook food under the sun and the solar cooking really attracts those creative kids.A. amazingB. amazedC. amaze
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Neurons that conduct impulses from the central nervous system to muscles or glands are referred to as()。
A、afferentB、associationC、voluntaryD、efferentE、sensory
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听力原文：In the United States, the Federal Gold Reserve acts as the central bank.(2)A．In the US, the Federal Gold Reserve acts as the central bank.B．In the US, the central bank is the commercial bank.C．In the US, there is no central bank.D．In the US, the central bank is not so important.
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A mean sun is used as the reference for solar time for three reasons. Which reason is NOT a cause for use of a mean sun?A.The motion of the apparent sun is along the eclipticB.Measurement of time is along the celestial equatorC.The speed of the Earth's revolution is not constantD.There are variations in the Earth's rotational speed
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The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!The Earth is quite safe with a magnetic field surrounding it to protect it from the attack by the solar wind.A: RightB: WrongC: Not mentioned
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The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!You cannot see the Northern Lights unless you are in Alaska or Canada.A: RightB: WrongC: Not mentioned
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The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!The Sun's gravity is too weak to keep its plasma from flowing to the Earth.A: RightB: WrongC: Not mentioned
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California Gives Green Light to Space Solar PowerEnergy beamed down from space is one step closer to reality,now that California has given the green light to an agreement that would see the Pacific Gas and Electric Company buy 200 megawatts（兆瓦）of power beamed down from solar-power satellites beginning in 2016.But some major challenges will have to beovercome if the technology is to be used widely.A start-up company called Solaren is designing the satellites,which it says will use radio waves to beamenergy down to a receiving station on Earth.The attraction of collecting solar power in space is the almost uninterrupted sunshine available in geo- synchronous（与地球同步的）orbit. Earth-based solar cells , by contrast , can only collect sun light during day-time and when skies are clear.But space-based solar power must grapple（努力克服）with the high cost per kilogram of launching things in- to space,says Richard Schwartz of Purdue University in West Lafayette,Indiana."if you're talking about it being economically viable for power of the Earth,it's a tough go,"he says.Cal Boerman,Solaren's director of energy services,says the company designed its satellites with a view to keeping launch costs down."We knew we had to come up with a different,revolutionary design,"he says. A patent the company has won describes ways to reduce the system's weight,including using inflatable mir- rors to focus sunlight on solar cells,so a smaller number can collect the same amount of energy.But using mirrors introduces other challenges,including keeping the solar cells from overheating,says Schwartz."You have to take care of heat dissipation（散发）because you're now concentrating a lot of energy in one place,"he says.According to the company's patent,Solaren's solar cells will be connected to radia-tors to help keep them cool.Though Boerman says the company believes it can make space-based solar power work,it is not expec-ting to crowd out other forms of renewable energy.Laws in California and other states require increasing use of renewable energy in coming years,he points out."To meet those needs,we're going to need all types of renewable energy sources,"he says.Inflatable mirrors are used to reduce the weight of the space-based solar power system.A:RightB:WrongC:Not mentioned
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第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The solar wind comes into being as a result of_______.A:disappearance of the Sun's gravityB:unpredictable weather of the SunC:fast flow of energy away from the SunD:a stream of particles being blown away
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New Comet FoundThere's a newfound comet closing in on the sun,and when it gets here in 2013,you may be able to see it with your naked eye.Astronomers stumbled upon the icy interloper on June 5 while searching for potentially hazardous asteroids（小行星）.Equipped with the world's largest digital camera , the University of Hawaii's Pan-STARRS team snagged a faint image of the odd object while it was more than 700 million miles away , between the orbits of Jupiter（木星）and Saturn（土星）."Almost everything we find is an asteroid,but this object was suspicious,"said Richard Wainscoat,co-discoverer of the comet and an astronomer at the University of Hawaii."Unlike asteroids, which appear point-like in images,the telltale sign that gave it away was its fuzzy appearance."By March 2013 the comet,named C/2011 L4(PANSTARRS),is expected to come within 30 million miles of the sun一closer even than the innermost（最深处）planet, Mercury（水星）.When the comet makes its closest approach to the sun,most of its ices will vaporize,adding to its hazy envelope of gas and dust and producing the familiar tail. This denser envelope,or coma, should boost the comet to peak brightness,making it potentially visible to the naked eye low in the western horizon just after sunset.While there is no danger of collision with Earth,preliminary calculations of the comet's orbit show that this may be its first and final trip through the solar system."It may be coming around the sun for the first and only time,only to be ejected from the solar system,never to return,"Wainscoat said."Since we don't have a lot of data on it,we really don't know the orbit well enough right now, and it will take up to two months of observations to find out."Astronomers believe C/2011 L4 may be a runaway from the Oort cloud（奥尔特云）,a reservoir of billions of hibernating（蛰伏）comets that orbits about 100,000 times farther than the distance between Earth and the sun.The fact that it's going around the back of the sun from our point of view may ultimately affect the comet's visibility,but a lot will depend on how close the body actually gets to the sun.Also, whether the comet is north or south of the sun when it reaches peak brightness will determine which hemisphere on Earth gets the better view.The newfound comet is made from mercury.A:Right B:Wrong C:Not mentiond
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New Comet FoundThere's a newfound comet closing in on the sun,and when it gets here in 2013,you may be able to see it with your naked eye.Astronomers stumbled upon the icy interloper on June 5 while searching for potentially hazardous asteroids（小行星）.Equipped with the world's largest digital camera , the University of Hawaii's Pan-STARRS team snagged a faint image of the odd object while it was more than 700 million miles away , between the orbits of Jupiter（木星）and Saturn（土星）."Almost everything we find is an asteroid,but this object was suspicious,"said Richard Wainscoat,co-discoverer of the comet and an astronomer at the University of Hawaii."Unlike asteroids, which appear point-like in images,the telltale sign that gave it away was its fuzzy appearance."By March 2013 the comet,named C/2011 L4(PANSTARRS),is expected to come within 30 million miles of the sun一closer even than the innermost（最深处）planet, Mercury（水星）.When the comet makes its closest approach to the sun,most of its ices will vaporize,adding to its hazy envelope of gas and dust and producing the familiar tail. This denser envelope,or coma, should boost the comet to peak brightness,making it potentially visible to the naked eye low in the western horizon just after sunset.While there is no danger of collision with Earth,preliminary calculations of the comet's orbit show that this may be its first and final trip through the solar system."It may be coming around the sun for the first and only time,only to be ejected from the solar system,never to return,"Wainscoat said."Since we don't have a lot of data on it,we really don't know the orbit well enough right now, and it will take up to two months of observations to find out."Astronomers believe C/2011 L4 may be a runaway from the Oort cloud（奥尔特云）,a reservoir of billions of hibernating（蛰伏）comets that orbits about 100,000 times farther than the distance between Earth and the sun.The fact that it's going around the back of the sun from our point of view may ultimately affect the comet's visibility,but a lot will depend on how close the body actually gets to the sun.Also, whether the comet is north or south of the sun when it reaches peak brightness will determine which hemisphere on Earth gets the better view.The ices of the comet will vaporize while heading to the sun.A:Right B:Wrong C:Not mentiond
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New Comet FoundThere's a newfound comet closing in on the sun,and when it gets here in 2013,you may be able to see it with your naked eye.Astronomers stumbled upon the icy interloper on June 5 while searching for potentially hazardous asteroids（小行星）.Equipped with the world's largest digital camera , the University of Hawaii's Pan-STARRS team snagged a faint image of the odd object while it was more than 700 million miles away , between the orbits of Jupiter（木星）and Saturn（土星）."Almost everything we find is an asteroid,but this object was suspicious,"said Richard Wainscoat,co-discoverer of the comet and an astronomer at the University of Hawaii."Unlike asteroids, which appear point-like in images,the telltale sign that gave it away was its fuzzy appearance."By March 2013 the comet,named C/2011 L4(PANSTARRS),is expected to come within 30 million miles of the sun一closer even than the innermost（最深处）planet, Mercury（水星）.When the comet makes its closest approach to the sun,most of its ices will vaporize,adding to its hazy envelope of gas and dust and producing the familiar tail. This denser envelope,or coma, should boost the comet to peak brightness,making it potentially visible to the naked eye low in the western horizon just after sunset.While there is no danger of collision with Earth,preliminary calculations of the comet's orbit show that this may be its first and final trip through the solar system."It may be coming around the sun for the first and only time,only to be ejected from the solar system,never to return,"Wainscoat said."Since we don't have a lot of data on it,we really don't know the orbit well enough right now, and it will take up to two months of observations to find out."Astronomers believe C/2011 L4 may be a runaway from the Oort cloud（奥尔特云）,a reservoir of billions of hibernating（蛰伏）comets that orbits about 100,000 times farther than the distance between Earth and the sun.The fact that it's going around the back of the sun from our point of view may ultimately affect the comet's visibility,but a lot will depend on how close the body actually gets to the sun.Also, whether the comet is north or south of the sun when it reaches peak brightness will determine which hemisphere on Earth gets the better view.C/2011 L4 will hit Earth in 2013.A:Right B:Wrong C:Not mentiond
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New Comet FoundThere's a newfound comet closing in on the sun,and when it gets here in 2013,you may be able to see it with your naked eye.Astronomers stumbled upon the icy interloper on June 5 while searching for potentially hazardous asteroids（小行星）.Equipped with the world's largest digital camera , the University of Hawaii's Pan-STARRS team snagged a faint image of the odd object while it was more than 700 million miles away , between the orbits of Jupiter（木星）and Saturn（土星）."Almost everything we find is an asteroid,but this object was suspicious,"said Richard Wainscoat,co-discoverer of the comet and an astronomer at the University of Hawaii."Unlike asteroids, which appear point-like in images,the telltale sign that gave it away was its fuzzy appearance."By March 2013 the comet,named C/2011 L4(PANSTARRS),is expected to come within 30 million miles of the sun一closer even than the innermost（最深处）planet, Mercury（水星）.When the comet makes its closest approach to the sun,most of its ices will vaporize,adding to its hazy envelope of gas and dust and producing the familiar tail. This denser envelope,or coma, should boost the comet to peak brightness,making it potentially visible to the naked eye low in the western horizon just after sunset.While there is no danger of collision with Earth,preliminary calculations of the comet's orbit show that this may be its first and final trip through the solar system."It may be coming around the sun for the first and only time,only to be ejected from the solar system,never to return,"Wainscoat said."Since we don't have a lot of data on it,we really don't know the orbit well enough right now, and it will take up to two months of observations to find out."Astronomers believe C/2011 L4 may be a runaway from the Oort cloud（奥尔特云）,a reservoir of billions of hibernating（蛰伏）comets that orbits about 100,000 times farther than the distance between Earth and the sun.The fact that it's going around the back of the sun from our point of view may ultimately affect the comet's visibility,but a lot will depend on how close the body actually gets to the sun.Also, whether the comet is north or south of the sun when it reaches peak brightness will determine which hemisphere on Earth gets the better view.Astronomers gets many details about the solar system.A:Right B:Wrong C:Not mentiond
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单选题Oil is a nonrenewable resource, whereas sunshine is limitless. So why not run cars on solar power? Because a car powered by solar collecting panels would be fine on a sunny day, but as soon as the sun went behind a cloud, the car would no longer function. Which of the following is presupposed in the argument against running a car on solar power?A
Solar power is cleaner than fossil fuels, and it involves less geopolitical risk.B
In most of the northern hemisphere, it can be expected that more than 150 days a year will be cloudy.C
No system exists for storing solar energy for a car’s use when the car is not in direct sunlight.D
No one has yet introduced a commercially viable process for mass-producing solar cells that convert more than 10 percent of incoming sunlight into usable energy.E
Consumers accustomed to the rapid acceleration of gasoline-powered cars will not accept the weak acceleration of solar-powered cars.
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单选题Many athletes use yoga to enhance their flexibility and so that they might improve their mind-body awareness.A
and so that they might improve their mind-body awarenessB
and to improve their mind-body awarenessC
as well as improving their mind-body awarenessD
and for improving their mind-body awarenessE
and improve their mind-body awareness also
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单选题Written in central Canada in the early part of the twentieth century, _______ , depicts life in Manitoda.A
The Midnight Sunwas Victor Frank’s last novelB
Victor Frank’s last novel was The Midnight SunC
The Midnight Sun, which was Victor Frank’s last novelD
Which was Victor Frank’s last novel, The Midnight Sun
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单选题A mean sun is used as the reference for solar time for three reasons. Which reason is NOT a cause for use of a mean sun?（）A
The motion of the apparent sun is along the eclipticB
Measurement of time is along the celestial equatorC
The speed of the Earth's revolution is not constantD
There are variations in the Earth's rotational speed
考题
单选题As an alternative to the conventional seawater cooling system, is based on principles about cooler locations, （）flow control and preheating, but with a central cooler and one additional set of pumps（）.A
the central cooling system, differentB
the central cooling system, the sameC
the open cooling system, differentD
the open cooling system, the same
考题
单选题We learn from the passage that ______.A
all living things on the earth depend on the sun for their foodB
a forest looks dark in winter because it absorbs solar energyC
only 0.023 of the energy from the sun is made use of on the earthD
greenhouse gases allow heat energy to escape from the earth’ s surface
考题
单选题Written in central Canada in the early part of the twentieth century, _____, depicts life in Manitoda.A
The Midnight Sun was Victor Frank’s last novelB
Victor Frank’s last novel was The Midnight SunC
The Midnight Sun, which was Victor Frank’s last novelD
Which was Victor Frank’s last novel, The Midnight Sun
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