Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times No, the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.
According to evolutionary theory of sleep, evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However, sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent.
The evolutionary theory explain the differences in sleep among creatures. Why do cats, for instance, sleep so much, while horses sleep so little Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value. Moreover, they cannot afford to sleep too long or too deeply, because their survival depends on their ability to run away from attackers.
Evolution has programmed man to sleep at night chiefly to help him ______.

A:keep up a regular pattern of life B:prevent trouble that comes looking for him C:avoid danger and inefficient labor D:restore his bodily functions

"I’ve never met a human worth cloning," says cloning expert Mark Westhusin from the cramped confines of his lab at Texas A & M University. "It’s a stupid endeavor.’ That’s an interesting choice of adjective, coming from a man who has spent millions of dollars trying to clone a 13-year-old dog named Missy. So far, he and his team have not succeeded, though they have cloned two calves and expect to clone a cat soon. They just might succeed in cloning Missy later this year--or perhaps not for another five years. It seems the reproductive system of man’s best friend is one of the mysteries of modem science.
Westhusin’s experience with cloning animals leaves him vexed by all this talk of human cloning. In three years of work on the Missyplicity project, using hundreds upon hundreds of canine eggs, the A&M team has produced only a dozen or so embryos carrying Missy’s DNA. None have survived the transfer to a surrogate mother. The wastage of eggs and the many spontaneously aborted fetuses may be acceptable when you’re dealing with cats or bulls, he argues, but not with humans. "Cloning is incredibly inefficient, and also dangerous," he says.
Even so, dog cloning is a commercial opportunity, with a nice research payoff. Ever since Dolly, the sheep, was cloned in 1997, Westhusin’s phone at A&M College of Veterinary Medicine has been ringing busily. Cost is no obstacle for customers like Missy’s mysterious owner, who wishes him remain unknown to protect his privacy. He’s plopped down $ 3. 7 million so far to fund the research because he wants a twin to carry on Missy’s fine qualities after she dies. But he knows her clone may not have her temperament. In a statement of purpose, Missy’s owner and the A&M team say they are "both looking forward to studying the ways that her clone differs from Missy."
The fate of the dog samples will depend on Westhusin’s work. He knows that even if he gets a dog viably pregnant, the offspring, should they survive, will face the problems shown at birth by other cloned animals: abnormalities like immature lungs and heart and weight problems. "Why would you ever want to clone humans," Westhusin asks, "when we’re not even close to getting it worked out in animals yet/
Which of the following best represents Mr. Westhusin’s attitude toward cloning

A:Animal cloning is a stupid attempt. B:Human cloning is not yet close to getting it worked out. C:Cloning is too inefficient and should be stopped. D:Animals cloning yes, and human cloning at least not now.

More than 40 million Americans between the ages of 5 and 18 attend schools throughout the United States. About 2 million school-age children are taught at home. While home schooling offers an alternative to the school environment, it has become a controversial issue.
Many public school advocates take a harsh attitude toward home schoolers, perceiving their actions as the ultimate slap in the face of public education and a damaging move for the children. Yet, as public school officials realize they stand little to gain by remaining hostile to the home-school population, the hard lines seem to be softening a bit. Some public schools have moved closer to tolerance, and，even in some cases, are seeking cooperation with home schoolers. " We are becoming relatively tolerant of home schoolers. Let’s give the kids access to public school so they’ll see it’s not as terrible as they’ve been told, and they’ll want to come back, " says John Marshall, an education official.
Perhaps, but don’t count on it, say home-school advocates. Some home schoolers oppose that public school system because they have strong convictions that their approach to education—whether fueled by religious belief or the individual child’s interests and natural pace—is best. Other home schoolers contend " not so much that the schools teach heresy, but that schools teach whatever they teach inappropriately." "These parents are highly independent and strive to ’take responsibility’ for their own lives within a society that they define as bureaucratic and inefficient. " says Van Gallon.
But Howard Carol, spokesman for America’s largest teachers union, argues that home schooling parents are trying to hide their children from the real world, says Van Gallon. " Maybe we are going to run into people with problems, people that have a drug problem, people that have an alcohol problem, and teenage pregnancy. We have many problems that happen in our society and many of the children are victims. But shielding the children from the real mix of what happens every day is denying them something that they are going to need later in life. " Mr. Carol also questioned the competence of parents as teachers though he admitted that some home schoolers do better academically. " We want to make sure that a student is not denied the full range of curriculum experiences and appropriate materials, especially now with the new technology that is being introduced and the costs involved there. "
" The success of home schooling has been documented in standardized test scores administered by public school officials, " says Frank Bernet, the executive director of the National Association of College Admission Councilors. " I know why they are doing it, but I wonder why they can’t work with school officials and teachers to make the school what they want it to be. " The response from home schoolers: " We have tried that. NOW it’s time to strike out on our own. /
Public school teaching, in the opinions of home school advocates, is______.

A:systematic B:inefficient C:uninteresting D:superficial

More than 40 million Americans between the ages of 5 and 18 attend schools throughout the United States. About 2 million school-age children are taught at home. While home schooling offers an alternative to the school environment, it has become a controversial issue.
Many public school advocates take a harsh attitude toward home schoolers, perceiving their actions as the ultimate Slap in the face of public education and a damaging move for the children. Yet, public school officials realize they stand little to gain by remaining hostile to the home-school population, the hard line seem to be softening a bit. Some public schools have moved closer to tolerance, and, even in some cases, are seeking cooperation with home schoolers." We are becoming relatively tolerant of home schoolers. Let’s give the kids access to public school so they’ll see it’s not as terrible as they’ve been told, and they’ll want to come back," says John Marshall, an education official.
Perhaps, but don’t count on it, say home-school advocates. Some home schoolers oppose that public school system because they have strong convictions that their approach to education—whether fueled by religious belief or the individual child’s interests and natural place—is best. Other home schoolers contend "not 80 much that the schools teach heresy, but that schools teach whatever they teach inappropriately," says Van Gallon. "These parents are highly independent and strive to take responsibility for their own lives within a society that they define as bureaucratic and inefficient."
But Howard Carol, spokesman for America’s largest teachers union, argues that home schooling parents are trying to hide their children from the real world. "Maybe we are going to run into people with problems, people that have a drug problem, people that have an alcohol problem, and teenage pregnancy. We have many problems that happen in our society and many of the children are victims. But shielding the children from the real mix of what happens every day is denying them something that they are going to need later in life. "Mr. Carol also questioned the competence of parents as teachers though he admitted that some home schoolers do better academically. "We want to make sure that a student is not denied the full range of curriculum experiences and appropriate materials, especially now with the new technology that is being introduced and the costs involved there."
"The success of home schooling has been documented in standardized test scores administered by public school officials," says Frank Bernet, the executive director of the National Association of College Admission Councilors. "I know why they are doing it, but I wonder why they can’t work with school officials and teachers to make the school what they want it to be." The response from home schoolers: "We have tried that. Now it’s time to strike out on our own./
Public school teaching, in the opinions of home school advocates, is

A:systematic. B:inefficient. C:uninteresting. D:superficial.

More than 40 million Americans between the ages of 5 and 18 attend schools throughout the United States. About 2 million school-age children are taught at home. While home schooling offers an alternative to the school environment, it has become a controversial issue.
Many public school advocates take a harsh attitude toward home schoolers, perceiving their actions as the ultimate slap in the face of public education and a damaging move for the children. Yet, as public school officials realize they stand little to gain by remaining hostile to the home-school population, the hard lines seem to be softening a bit. Some public schools have moved closer to tolerance, and，even in some cases, are seeking cooperation with home schoolers. " We are becoming relatively tolerant of home schoolers. Let’s give the kids access to public school so they’ll see it’s not as terrible as they’ve been told, and they’ll want to come back, " says John Marshall, an education official.
Perhaps, but don’t count on it, say home-school advocates. Some home schoolers oppose that public school system because they have strong convictions that their approach to education—whether fueled by religious belief or the individual child’s interests and natural pace—is best. Other home schoolers contend " not so much that the schools teach heresy, but that schools teach whatever they teach inappropriately." "These parents are highly independent and strive to ’take responsibility’ for their own lives within a society that they define as bureaucratic and inefficient. " says Van Gallon.
But Howard Carol, spokesman for America’s largest teachers union, argues that home schooling parents are trying to hide their children from the real world, says Van Gallon. " Maybe we are going to run into people with problems, people that have a drug problem, people that have an alcohol problem, and teenage pregnancy. We have many problems that happen in our society and many of the children are victims. But shielding the children from the real mix of what happens every day is denying them something that they are going to need later in life. " Mr. Carol also questioned the competence of parents as teachers though he admitted that some home schoolers do better academically. " We want to make sure that a student is not denied the full range of curriculum experiences and appropriate materials, especially now with the new technology that is being introduced and the costs involved there. "
" The success of home schooling has been documented in standardized test scores administered by public school officials, " says Frank Bernet, the executive director of the National Association of College Admission Councilors. " I know why they are doing it, but I wonder why they can’t work with school officials and teachers to make the school what they want it to be. " The response from home schoolers: " We have tried that. NOW it’s time to strike out on our own. /

A:systematic B:inefficient C:uninteresting D:superficial

Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times No, the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.
According to evolutionary theory of sleep, evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However, sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent.
The evolutionary theory explain the differences in sleep among creatures. Why do cats, for instance, sleep so much, while horses sleep so little Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value. Moreover, they cannot afford to sleep too long or too deeply, because their survival depends on their ability to run away from attackers.
Evolution has programmed man to sleep at night chiefly to help him ______.

A:keep up a regular pattern of life B:prevent trouble that comes looking for him C:avoid danger and inefficient labor D:restore his bodily functions

Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times No, the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.
According to evolutionary theory of sleep, evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However, sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent.
The evolutionary theory explain the differences in sleep among creatures. Why do cats, for instance, sleep so much, while horses sleep so little Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value. Moreover, they cannot afford to sleep too long or too deeply, because their survival depends on their ability to run away from attackers.
Evolution has programmed man to sleep at night chiefly to help him ______.

A:keep up a regular pattern of life B:prevent trouble that comes looking for him C:avoid danger and inefficient labor D:restore his bodily functions