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[单选题]
Humans have been exploring the outer space _____we first stepped on the moon.
A.when
B.since
C.for
D.once
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题目内容
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A.when
B.since
C.for
D.once
如果结果不匹配，请 联系老师 获取答案
更多“Humans have been exploring the…”相关的问题
A.Animals have driven humanitys success.
B.Tool-making and language are uniquely human habits.
C.Employing wolves is uniquely human habit.
D.People live with animals everywhere.
(41~45) Researchers have found that drugs used to treat human seizures can delay aging in worms by as much as 50 percent. The roundworms used for the study are similar to humans in their molecular makeup, raising the
possibility that the drugs could also extend the life span of humans。
第41题：“By finding a class of drugs that delays aging we have found a relationship between the function of the nervous system and aging that was not well understood, ” said Kerry Komfeld, a geneticist at the Washington University School of Medicine in St. Louis, Missouri. The findings are detailed this week in the journal Science。 The discovery came out of the thesis work by one of Komfeld’s graduate students, Kimberley Evason. About four years ago, Evason began exposing groups of the roundworm Caenorhabditis elegans to commercially available drugs to see if the drugs would delay aging or promote longevity。
A. But Komfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “What’s very encouraging is that these drugs were developed to treat humans, and they are well understood, because they’ve been used for a long time, ” he said。
B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the worms-in the case of one drug, by almost 50 percent. “This was a big surprise to use, Komfeld said. ”“We didn’t think anticonvulsant drugs had any particular relationship to aging. That connection was completely unexpected. ”
C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult to know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long。
D. “Somehow the neural activity seems to regulate the aging of all of the body the skin, musculature, and reproductive tract, ” Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we don’t know how it does that. ”
E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of both humans and worms, the findings hint at a link between neural activity and aging。
F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worm’s genome has been sequenced。
G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof, says Kornfeld optimistically. ”
Human' s Hands
Archaeological records--paintings, drawings, and drawings of humans engaged in activities involving the use of hands--indicate that humans have been predominantly right - handed for more than 5,000 years. In ancient Egyptian artwork, for example, the fight-hand is depicted us the dominant one in about 90 per- cent of the examples. Fracture or wear patterns on tools also indicate that a majority of ancient people were fight - handed.
Cro - Magnon cave paintings some 27,000 years old commonly show outlines of human hands made by placing one hand against the cave wall and applying paint with the other. Children today make similar. out- lines of their hands with crayons on paper. With few exceptions, left hands of Cro-Manganese are displayed on cave wails, indicating that the paintings were usually done by right-handers.
Anthropological evidence pushes the record of' handedness nearly human ancestors back to at least 1.4 million years ago. One important line of evidence comes from flaking patterns of stone cores used in toolmaking: implements flaked with a clockwise motion (indicating a right -handed toolmaker) can be distinguished from those flaked with a counter- clockwise rotation (indicating a left- handed toolmaker).
Even scratches found on fossil human teeth offer clues. Ancient humans are thought to have cut meat into strips by holding it between their teeth and slicing it with stone knives, as do the present - day Inuit. Occasionally the knives slip and leave scratches on the users' teeth. Scratches made with a left - to - right stroke direction (by right- handers) are more common than scratches in the opposite direction (made by lefthanders).
Still other evidence comes from cranial morphology: scientists think that physical differences between the right and left sides of the interior of the skull indicate subtle physical differences between the two sides of the brain. The variation between the hemispheres corresponds to which Side of the body is used to perform. specific activities. Such studies, as well as studies of tool use, indicate that right - or left - sided dominance is not exclusive to modern Homo sapiens. Populations of Neanderthals, such as Homo erects and Homo habilis, seem to have been predominantly right -handed, as we are.
What is the main idea of the passage？
A．Human ancestors became predominantly right- handed when they began to use tools.
B．It is difficult to interpret the significance of anthropological evidence concerning tool use.
C．Human and their ancestors have been predominantly right - handed for over a million years.
D．Human ancestors were more skilled at using both hands than modern humans.
Many Native Americans closely resemble Asians. This has led most scientists to(1)believe something about Native Americans. They think that most Native Americans(2)from a distant group of people. These people(3)from Siberia across the Bering Strait, between 17,000-11,000 years ago. The exact time and 4 is still under question. That is, it is still a(n)(5)of debate. The time they traveled and the route they took is still being argued, as is whether it happened(6).
(7)recently, some anthropologists (人类学家) argued that the migration occurred 12,000 years ago. However, there are a number of difficulties with this theory —(8)particular, the presence of people in the Americas earlier than one might think. There is growing evidence of human(9)in Brazil and Chile 11,500 years ago or earlier. There is also(10)of humans living in the Americas some 50,000 years ago.(11), other possibilities have been suggested.
They may have(12)the land bridge several thousand years earlier or they may have sailed along the western coast. However, some(13)this theory. They think that humans(14)skills for sailing during that era.
Some consider the genetic and cultural evidence for an Asian origin overwhelming. It should be noted,(15), that some other people are very upset at this idea. Many present-day Native Americans(16)the above theories. They say those who put forward such theories have political(17)They have their own traditional stories that offer(18)of where they came from. Their own stories claim that their(19)are different from what scientists say. Those accounts, though, have mostly been(20)by scholars. Therefore, the origin of Americans still remains a mystery to be explored.
Based on the results, the researchers concluded the rats were dreaming about the maze, (5)_____ re viewing what they had learned while awake to (6)_____ the memories.
Researchers have long known that animals go (7)_____ the same types of sleep phases that people do, including rapid-eye-movement (REM) sleep, which is when people dream. But (8)_____ the occasional twitching, growling or barking that any dog owner has (9)_____ in his or her sleeping pet, there's been (10)_____ direct evidence that animals (11)_____. If animals dream, it suggests they might have more (12)_____ mental functions than had been (13)_____.
"We have as humans felt that this (14)_____ of memory—our ability to recall sequences of experiences—was something that was (15)_____ human," Wilson said. "The fact that we see this in rodents (16)_____ suggest they can evaluate their experience in a significant way. Animals may be (17)_____ about more than we had previously considered."
The findings also provide new support for a leading theory for (18)_____ humans sleep—to solidify new learning. "People are now really nailing down the fact that the brain during sleep is (19)_____ its activity at least for the time immediately before sleep and almost undoubtedly using that review to (20)_____ or integrate those memories into more usable forms," said an assistant professor of psychiatry at Harvard Medical School.
A．related
B．retained
C．released
D．relieved
A. But Komfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “What’s very encouraging is that these drugs were developed to treat humans, and they are well understood, because they’ve been used for a long time, ” he said。
B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the worms-in the case of one drug, by almost 50 percent. “This was a big surprise to use, Komfeld said. ”“We didn’t think anticonvulsant drugs had any particular relationship to aging. That connection was completely unexpected. ”
C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult to know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long。
D. “Somehow the neural activity seems to regulate the aging of all of the body the skin, musculature, and reproductive tract, ” Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we don’t know how it does that. ”
E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of both humans and worms, the findings hint at a link between neural activity and aging。
F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worm’s genome has been sequenced。
G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof, says Kornfeld optimistically. ”
A. But Komfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “What’s very encouraging is that these drugs were developed to treat humans, and they are well understood, because they’ve been used for a long time, ” he said。
B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the worms-in the case of one drug, by almost 50 percent. “This was a big surprise to use, Komfeld said. ”“We didn’t think anticonvulsant drugs had any particular relationship to aging. That connection was completely unexpected. ”
C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult to know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long。
D. “Somehow the neural activity seems to regulate the aging of all of the body the skin, musculature, and reproductive tract, ” Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we don’t know how it does that. ”
E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of both humans and worms, the findings hint at a link between neural activity and aging。
F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worm’s genome has been sequenced。
G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof, says Kornfeld optimistically. ”
(25) all this means is that people develop "quasi theories" of human behavior, that is, theories that are not developed in a (an) (26) , scientific manner. When doing so, people believe they know (27) humans do the things they do.
Let's consider an example. In the United States people have been (28) with the increasing amount of crime for several years. The extent of crime bothers us; we ourselves could be victims. But it (29) bothers us that people behave in such ways. Why can such things happen？ We develop quasi theories. We (30) concerned about the high crime rate, but we now believe we (31) it: our criminal justice system is (32) ; people have grown selfish and inconsiderate as our moral values weaken (33) the influence of liberal ideas; too many people are (34) drugs. These explanations suggest possible solutions. (35) the courts; put more people in jail as examples to other lawbreaker. There is now hope that the problem of crime can be solved if only we (36) these solutions. Again, the world is no longer meaningless nor (37) so threatening. These quasi theories (38) serve a very important function for us. But how accurate are they？ How (39) will the suggested solutions be？ These questions must be answered with (40) to how people normally go about developing or attaining their quasi theories of human behavior.
A．reason
B．consider
C．understand
D．regard
【C1】
A．decreases
B．reductions
C．increases
D．additions
A. But Komfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “What’s very encouraging is that these drugs were developed to treat humans, and they are well understood, because they’ve been used for a long time, ” he said。
B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the worms-in the case of one drug, by almost 50 percent. “This was a big surprise to use, Komfeld said. ”“We didn’t think anticonvulsant drugs had any particular relationship to aging. That connection was completely unexpected. ”
C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult to know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long。
D. “Somehow the neural activity seems to regulate the aging of all of the body the skin, musculature, and reproductive tract, ” Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we don’t know how it does that. ”
E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of both humans and worms, the findings hint at a link between neural activity and aging。
F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worm’s genome has been sequenced。
G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof, says Kornfeld optimistically. ”
