D
As they migrate（迁移），butterflies and moths choose the winds they want to fly with，and they change their body positions if they start floating in the wrong direction．This new finding suggests that insects may employ some of the same methods that birds use for traveling long distances．Scientists have long thought that insects were simply at the mercy of the wind．
Fascinating as their skills of flight are，migrating behavior has been difficult to study in insects because many long distant trips happthousands of feet above ground．Only recently have scientists developed technologies that can detect such little creatures at such great heights．
To their surprise，though，the insects weren’t passive travelers on the winds．In autumn，for example，most light winds blew from the east，but the insects somehow sought out ones that carried them south and they positioned themselves to navigate directly to their wintering homes．
Even in the spring，when most winds flowed northward，the insects didn’t always go with the flow．If breezes weren’t blowing in the exact direction they wanted to go，the insects changed their body positions to compensate．Many migrating birds do the same thing．
The study also found，butterflies and moths actively flew within the air streams that pushed them along．By adding flight speeds to wind speeds，the scientists calculated that butterflies and moths can travel as fast as 100 kilometers an hour．The findings may have real-world applications．With climate warming，migrating insects are growing in number．Knowing how and when these pests move could help when farmers decide when to spray their crops．
71．What’s the main idea of the text?
A．Insects migrate with the seasons．     B．Wind helps insects greatly in migrating．
C．Windsurfing insects have real direction．D．Scientists have trouble in observing insects．
72．Scientists originally thought that____________．
A．insects always waited for their favourable winds
B．insects chose the winds they wanted to ride
C．insects were just blown about by the wind
D．insects positioned themselves in the winds
73．It is not easy to stuay the migrating behavior of the insects because____________
A．the little creatures can fly very fast     B．they have no regular migrating courses
C．the wind’s direction is hard to foresee    D．their flight is long and high above ground
74．We can learn from the text that______________.
A．insects fly in the way birds do
B．insects travel more easily in autumn
C．insects never position themselves when flying low
D．insects rest a lot when the wind pushes them along
75．According to the passage，the findings can              ．
A．increase insects in number         B．instruct farmers when to spray
C．prevent climate warming       D．help protect insects

Just as the world’s most respected scientific bodies have confirmed that the world is getting hotter, they have also stated that there is strong evidence that humans are driving the warming. Countless recent reports from the world’s leading scientific bodies have said the same thing. For example, a 2010 summary of climate science by the Royal Society stated that: “There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity.”
The idea that humans could change the planet’s climate may be counter-intuitive, but the basic science is well understood. Each year, human activity causes billions of tons of greenhouse gases to be released into the atmosphere. As scientists have known for years, these gases hold heat that would otherwise escape to space, wrapping the planet in an invisible blanket.
Of course, the planet’s climate has always been changing thanks to “natural” factors such as changes in solar or volcanic activity, or cycles relating the Earth’s going around the sun. According to the scientific literature, however, the warming recorded to date matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere – not the warming we would expect from other possible causes.
Even if scientists did discover another reasonable explanation for the warming observed so far, that would beg a difficult question. As Robert Henson puts it in The Rough Guide to Climate Change, “If some newly discovered factor can account for the climate change, then why aren’t carbon dioxide and the other greenhouse gases producing the warming that basic physics tells us they should be?”
The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without. That obviously isn’t possible, and so most scientists are careful not to state human influence as an absolute certainty.
【小题1】 In most scientists’ opinion, the global warming is mainly caused by ________.

Just as the world’s most respected scientific bodies have confirmed that the world is getting hotter, they have also stated that there is strong evidence that humans are driving the warming. Countless recent reports from the world’s leading scientific bodies have said the same thing. For example, a 2010 summary of climate science by the Royal Society stated that: “There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity.”
The idea that humans could change the planet’s climate may be counter-intuitive(与直觉不符的), but the basic science is well understood. Each year, human activity causes billions of tons of greenhouse gases to be released（释放）into the atmosphere. As scientists have known for years, these gases hold heat that would otherwise escape to space, wrapping the planet in an invisible blanket.
Of course, the planet’s climate has always been changing thanks to “natural” factors(因素) such as changes in solar or volcanic（火山的）activity, or cycles relating the Earth’s going around the sun. According to the scientific literature, however, the warming recorded to date matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere – not the warming we would expect from other possible causes.
Even if scientists did discover another reasonable explanation for the warming observed so far, that would beg a difficult question. As Robert Henson puts it in The Rough Guide to Climate Change: “If some newly discovered factor can account for the climate change, then why aren’t carbon dioxide（二氧化碳）and the other greenhouse gases producing the warming that basic physics tells us they should be?”
The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without. That obviously isn’t possible, and so most scientists are careful not to state human influence as an absolute certainty.
【小题1】 In most scientists’ opinion, the global warming is mainly caused by ________.

Just as the world’s most respected scientific bodies have confirmed that the world is getting hotter, they have also stated that there is strong evidence that humans are driving the warming. Countless recent reports from the world’s leading scientific bodies have said the same thing. For example, a 2010 summary of climate science by the Royal Society stated that: “There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity.”

The idea that humans could change the planet’s climate may be counter-intuitive(与直觉不符的), but the basic science is well understood. Each year, human activity causes billions of tons of greenhouse gases to be released（释放）into the atmosphere. As scientists have known for years, these gases hold heat that would otherwise escape to space, wrapping the planet in an invisible blanket.

Of course, the planet’s climate has always been changing thanks to “natural” factors(因素) such as changes in solar or volcanic（火山的）activity, or cycles relating the Earth’s going around the sun. According to the scientific literature, however, the warming recorded to date matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere – not the warming we would expect from other possible causes.

Even if scientists did discover another reasonable explanation for the warming observed so far, that would beg a difficult question. As Robert Henson puts it in The Rough Guide to Climate Change: “If some newly discovered factor can account for the climate change, then why aren’t carbon dioxide（二氧化碳）and the other greenhouse gases producing the warming that basic physics tells us they should be?”

The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without. That obviously isn’t possible, and so most scientists are careful not to state human influence as an absolute certainty.

1. In most scientists’ opinion, the global warming is mainly caused by ________.

   A. solar activity                       

B. volcanic activity

C. the Earth’s going around the sun    

D. human activity

2.The text is developed by ________.

   A. giving typical examples

   B. following the order of space

   C. analyzing a theory and arguing it

   D. comparing and finding differences

3.The underline word “identical” means ________.

   A. totally different                    

B. exactly the same

   C. extremely important                  

D. relatively independent

4. Which of the following can be the best title?

   A. Are All the Scientists Really Scientific?

   B. Where Is Global Warming Leading Us to?

   C. Are Humans Definitely Causing Global Warming?

   D. What’s Relation of Global Warming and Greenhouse Gases?

Just as the world’s most respected scientific bodies have confirmed that the world is getting hotter, they have also stated that there is strong evidence that humans are driving the warming. Countless recent reports from the world’s leading scientific bodies have said the same thing. For example, a 2010 summary of climate science by the Royal Society stated that: “There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity.”
The idea that humans could change the planet’s climate may be counter-intuitive(与直觉不符的), but the basic science is well understood. Each year, human activity causes billions of tons of greenhouse gases to be released（释放）into the atmosphere. As scientists have known for years, these gases hold heat that would otherwise escape to space, wrapping the planet in an invisible blanket.
Of course, the planet’s climate has always been changing thanks to “natural” factors(因素) such as changes in solar or volcanic（火山的）activity, or cycles relating the Earth’s going around the sun. According to the scientific literature, however, the warming recorded to date matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere – not the warming we would expect from other possible causes.
Even if scientists did discover another reasonable explanation for the warming observed so far, that would beg a difficult question. As Robert Henson puts it in The Rough Guide to Climate Change: “If some newly discovered factor can account for the climate change, then why aren’t carbon dioxide（二氧化碳）and the other greenhouse gases producing the warming that basic physics tells us they should be?”
The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without. That obviously isn’t possible, and so most scientists are careful not to state human influence as an absolute certainty.

1. 1.

   In most scientists’ opinion, the global warming is mainly caused by ________.

   1. A.
      solar activity
   2. B.
      volcanic activity
   3. C.
      the Earth’s going around the sun
   4. D.
      human activity
2. 2.

   The text is developed by ________.

   1. A.
      giving typical examples
   2. B.
      following the order of space
   3. C.
      analyzing a theory and arguing it
   4. D.
      comparing and finding differences
3. 3.

   The underline word “identical” means ________.

   1. A.
      totally different
   2. B.
      exactly the same
   3. C.
      extremely important
   4. D.
      relatively independent
4. 4.

   Which of the following can be the best title?

   1. A.
      Are All the Scientists Really Scientific?
   2. B.
      Where Is Global Warming Leading Us to?
   3. C.
      Are Humans Definitely Causing Global Warming?
   4. D.
      What’s Relation of Global Warming and Greenhouse Gases?