When scientists set out to explore the roots of human laughter, some apes（类人猿） were just tickled（胳肢）to help. That’s how researchers made a variety of apes and some human babies laugh. After analyzing the sounds, they concluded that people and great apes inherited laughter from a shared ancestor that lived more than 10 million years ago. Experts praised the work, it gives strong evidence that ape laughter and human laughter are related through evolution（进化）.
Scientists have noted that apes make characteristic sounds during play or while being tickled, especially to signal that they’re interested in playing. It’s been suggested before that human laughter grew out of primate（灵长类动物） roots. But ape laughter doesn’t sound like human laughter. It may be slower noisy breathing. So what does that have to do with the human ha-ha? To investigate that, Marina Davila Ross and her colleagues carried out a detailed analysis of the sounds made by tickling three human babies and 21 other primates, apes included.
After measuring 11 features in the sound from each species, they tried to find out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online in the journal Current Biology. They also concluded that while human laughter sounds much different from ape laughter, their typical features could have come from the same ancestor.
Panksepp, who studies laughter-like responses in animals but didn’t participate in the new work, called the paper exciting. Panksepp’s own work concludes that even rats produce laughter in response to playing and tickling, with sounds that can hardly be heard by people. Robert Provine, a scientist, who wrote the book, Laughter: A Scientific Investigation, said the new paper showed some important clues, like ape sounds that hadn’t been realized before.
69. Why did the scientists analyze the laughter made by tickling human babies and apes?
A. To try to discover if they can make characteristic sounds.
B. To see if they interested in playing.
C. To find out if the laughter of apes and humans is related.
D. To find out the differences between humans and apes.
70. Based on Paragraph 3 we can know that researchers measured the features in the sound to ________.
A. find out ape sounds that hadn’t been realized before
B. find out relations among primates’ laughter
C. see what a family tree from each species looks like
D. make a report online in the journal Current Biology
71. What can be inferred from the last paragraph?
A. Panksepp spoke highly of the new research.
B. Rat laughter is likely to be related to ape laughter.
C. Robert Provine provided some new clues for the researchers.
D. Humans don’t enjoy listening to ape laughter.
72. What would be the best title for the passage?
A. Ape study explores evolution of laughter.
B. Apes like to laugh when being tickled.
C. Human laughter and ape laughter are different.
D. Laughter: A Scientific Investigation.

  When scientists set out to explore the roots of human laughter, some apes（类人猿） were just tickled（胳肢）to help. That’s how researchers made a variety of apes and some human babies laugh. After analyzing the sounds, they concluded that people and great apes inherited laughter from a shared ancestor that lived more than 10 million years ago. Experts praised the work, it gives strong evidence that ape laughter and human laughter are related through evolution（进化）.

Scientists have noted that apes make characteristic sounds during play or while being tickled, especially to signal that they’re interested in playing. It’s been suggested before that human laughter grew out of primate（灵长类动物） roots. But ape laughter doesn’t sound like human laughter. It may be slower noisy breathing. So what does that have to do with the human ha-ha? To investigate that, Marina Davila Ross and her colleagues carried out a detailed analysis of the sounds made by tickling three human babies and 21 other primates, apes included.

After measuring 11 features in the sound from each species, they tried to find out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online in the journal Current Biology. They also concluded that while human laughter sounds much different from ape laughter, their typical features could have come from the same ancestor.

Panksepp, who studies laughter-like responses in animals but didn’t participate in the new work, called the paper exciting. Panksepp’s own work concludes that even rats produce laughter in response to playing and tickling, with sounds that can hardly be heard by people. Robert Provine, a scientist, who wrote the book, Laughter: A Scientific Investigation, said the new paper showed some important clues, like ape sounds that hadn’t been realized before.

69. Why did the scientists analyze the laughter made by tickling human babies and apes?

A. To try to discover if they can make characteristic sounds.

B. To see if they interested in playing.

C. To find out if the laughter of apes and humans is related.

D. To find out the differences between humans and apes.

70. Based on Paragraph 3 we can know that researchers measured the features in the sound to ________.

A. find out ape sounds that hadn’t been realized before

B. find out relations among primates’ laughter

C. see what a family tree from each species looks like

D. make a report online in the journal Current Biology

71. What can be inferred from the last paragraph?

A. Panksepp spoke highly of the new research.

B. Rat laughter is likely to be related to ape laughter.

C. Robert Provine provided some new clues for the researchers.

D. Humans don’t enjoy listening to ape laughter.

72. What would be the best title for the passage?

A. Ape study explores evolution of laughter.

B. Apes like to laugh when being tickled.

C. Human laughter and ape laughter are different.

D. Laughter: A Scientific Investigation.

Section B

Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

E atmosphere  G. matched     H. reducing   I. carried      J. increase

Forests in the northern half of the globe could be growing faster now than they were 200 years ago as a result of climate change, according to a study of trees in eastern America. The trees appear to have faster growth rates due to longer growing seasons and higher concentrations (浓度) of carbon dioxide in the ___41___.

Geoffrey Parker, a scientist at the Smithsonian Environmental Research Centre in Edgewater. Maryland, said that the increase ha the rate of growth was unexpected and might be ___42___ to the higher temperatures and longer growing seasons documented in the region. The growth may also be influenced by the significant ___43___ in atmospheric CO2, he said.

"We made a list of reasons these forests could be growing faster and then excluded half of them," Dr. Parker said. Their study suggests that northern forests may become increasingly important in ___44___ the influence of man-made CO2 on the climate.

Dr. Parker and his colleagues have ___45___ out a detailed record of the trees on a(n) ___46___ basis since 1987. They calculated that due to the global warming the forest is producing   ___47___ tons of wood each year.

The scientists ___48___ the land with trees at different stages of growth and found that both young and old trees were showing increased growth rate. More than 90 per cent of the tree groups had grown by between two and four times faster than the scientists had ___49___ from estimates of the long-term rates of growth.

Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

Forests in the northern half of the globe could be growing faster now than they were 200 years ago as a result of climate change, according to a study of trees in eastern America. The trees appear to have faster growth rates due to longer growing seasons and higher concentrations (浓度) of carbon dioxide in the ___1.___.

Geoffrey Parker, a scientist at the Smithsonian Environmental Research Centre in Edgewater. Maryland, said that the increase ha the rate of growth was unexpected and might be ___2.___ to the higher temperatures and longer growing seasons documented in the region. The growth may also be influenced by the significant ___3.___ in atmospheric CO₂, he said.

"We made a list of reasons these forests could be growing faster and then excluded half of them," Dr. Parker said. Their study suggests that northern forests may become increasingly important in ___4.___ the influence of man-made CO₂ on the climate.

Dr. Parker and his colleagues have ___5.___ out a detailed record of the trees on a(n) ___6.___ basis since 1987. They calculated that due to the global warming the forest is producing   ___7.___ tons of wood each year.

The scientists ___8.___ the land with trees at different stages of growth and found that both young and old trees were showing increased growth rate. More than 90 per cent of the tree groups had grown by between two and four times faster than the scientists had ___9.___ from estimates of the long-term rates of growth.

  When scientists set out to explore the roots of human laughter, some apes（类人猿） were just tickled（胳肢）to help. That’s how researchers made a variety of apes and some human babies laugh. After analyzing the sounds, they concluded that people and great apes inherited laughter from a shared ancestor that lived more than 10 million years ago. Experts praised the work, it gives strong evidence that ape laughter and human laughter are related through evolution（进化）.

  Scientists have noted that apes make characteristic sounds during play or while being tickled, especially to signal that they’re interested in playing. It’s been suggested before that human laughter grew out of primate（灵长类动物） roots. But ape laughter doesn’t sound like human laughter. It may be slower noisy breathing. So what does that have to do with the human ha-ha? To investigate that, Marina Davila Ross and her colleagues carried out a detailed analysis of the sounds made by tickling three human babies and 21 other primates, apes included.

  After measuring 11 features in the sound from each species, they tried to find out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online in the journal Current Biology. They also concluded that while human laughter sounds much different from ape laughter, their typical features could have come from the same ancestor.

  Panksepp, who studies laughter-like responses in animals but didn’t participate in the new work, called the paper exciting. Panksepp’s own work concludes that even rats produce laughter in response to playing and tickling, with sounds that can hardly be heard by people. Robert Provine, a scientist, who wrote the book, Laughter: A Scientific Investigation, said the new paper showed some important clues, like ape sounds that hadn’t been realized before.

69. Why did the scientists analyze the laughter made by tickling human babies and apes?

   A. To try to discover if they can make characteristic sounds.

   B. To see if they interested in playing.

   C. To find out if the laughter of apes and humans is related.

   D. To find out the differences between humans and apes.

70. Based on Paragraph 3 we can know that researchers measured the features in the sound to ________.

   A. find out ape sounds that hadn’t been realized before

   B. find out relations among primates’ laughter

   C. see what a family tree from each species looks like

   D. make a report online in the journal Current Biology

71. What can be inferred from the last paragraph?

   A. Panksepp spoke highly of the new research.

   B. Rat laughter is likely to be related to ape laughter.

   C. Robert Provine provided some new clues for the researchers.

   D. Humans don’t enjoy listening to ape laughter.

72. What would be the best title for the passage?

   A. Ape study explores evolution of laughter.

   B. Apes like to laugh when being tickled.

   C. Human laughter and ape laughter are different.

   D. Laughter: A Scientific Investigation.