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[单选题]
Scientists think that the continents()always where they ()today.
A.weren't; were
B.aren't, were
C.weren't; are
D.aren't; are
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题目内容
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如果结果不匹配，请 联系老师 获取答案
题目内容
（请给出正确答案）
A.weren't; were
B.aren't, were
C.weren't; are
D.aren't; are
如果结果不匹配，请 联系老师 获取答案
更多“Scientists think that the cont…”相关的问题
What does Alex Winston think of her age？
A．She desires to look younger.
B．She is excited that she looks mature.
C．She doesn"t have a problem with her age.
D．She wishes she could go back to her teenage years.
A B C
body，and think up a way to recover.
D
Which of the following is true of Livingston？
A．He thinks he has discovered a new possibility in the link between sun spots and the weather on the Earth.
B．He has great doubts about the theory that the sun' s frequent changes have an influenced on the Earth' s climate.
C．He has been recently informed by other scientists of the possibility that more sun spots will appear.
D．He does not think the causes of the sun spots will be fully revealed by scientists in the near future.
Language is always changing.The earliest known languages had complicated grammar but a small, limited vocabulary.Over the centuries, the grammar changed, and the vocabulary grew.For example, the English and Spanish people who came to America during the sixteenth and seventeenth centuries gave names to all the new plants and animals they found.In this way, hundreds of new words were introduced into English and Spanish vocabularies.Today life is changing very fast, and language is changing fast, too.
There are several major language families in the world.Some scientists say there are nine main families, but other scientists divide them differently.The languages in each family are related, and scientists think that they came from the same parent language.
We learn our own languages by listening and copying.We do this without studying or thinking about it.But learning a foreign language takes a lot of study and practice.
(1).What do all languages in the world have？
A.Complicated vocabularies
B.Single grammar
C.Large vocabularies
D.A system of sounds
(2).What does the earliest known languages have？
A.Different word orders
B.Difficult grammar
C.Difficult vocabularies
D.Easy sound system
(3).What did the English and Spanish people who came to America do？
A.They gave names to different animals
B.They found many new plants and animals
C.They changed the grammar of English and Spanish
D.They introduced new words into English and Spanish
(4).Scientists think that the languages in each family_________________________.
A.are related
B.should be divided differently
C.should be separated
D.are not very different
(5).According to the passage, we learn our own language by_________________________.
A.thinking about it
B.practicing it
C.listening and copying
D.studying it
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.
Most musicians agree that the best violins(小提琴) were made in Cremona, Italy, about 200years ago. They even sound better than violins made today. Violin makers and scientists try to makeinstruments(乐器)like the Italian violins,however,they are not the same. Why are these old Italianviolins so special？ No one really knows. But many people think they have an answer.
Some people think it is the age of the violins. But there is a problem here. Not all old violins sound wonderful. Only the old violins from Cremona are special. So age cannot be the answer.
Other people think the secret to those violins is the wood. It must be from certain kinds of trees.It must not be too young or too old. Perhaps the violin makers of Cremona knew something specialabout wood for violins.
But the kind of wood may not be so important. It may be more important to cut the wood in aspecial way. Wood for a violin must be cut into the right size and shape. The smallest difference willchange the sund of the violin. Musicians sometimes think that this is the secret of the Italians.
Size and shape may not be the answer either. Scientists make new violins that are exactly the same size and shape. But the new ones still do not sound as good as the old ones. Some scientiststhink the secret may be the varnish (清漆).It makes the wood look shiny, but it also helps the soundof the instrument. Since no one knows what the Italian violin makers used in their varnish, no one canmake the same varnish today.
There may never be other violins like the violins of Cremona. And there are not many of the old violins left. So these old violins from Cremona become more and more precious. What would be the best title for the text？
A.The Secrets of Cremona Violins.
B.The History of Cremona Violins.
C.The Making of Italian Violins.
D.The Studies of Italian Violins.
What is still not clear about Cremona violins？A.The shape
B.The wood
C.The size
D.The varnish
Which of the following Words can best describe Cremona violins？A.Light
B.Shining
C.Valuable
D.Modern
请帮忙给出每个问题的正确答案和分析，谢谢！
阅读材料，回答题。
Man cannot go on increasing his number at the present rate. In the next 30 years man will faca period of crisis. Some experts believe that there will be a widespread food___ 51 ____. Other experthink this is too pessimistic (悲观的), and that man can prevent things from___ 52 ____worse tha they are now. But remember that two thirds of the people in the world are under-nourished or stmving now.
One thing that man can do is to limit the___ 53 ____of babies born. The need for this is obvious but it is not easy to achieve. People have to be___ 54 ____to limit their families. In the countries of the population___ 55 ____, many people like big families. The parents think that this makes a bigger income for the family and ensures there will be someone in the family who will look___ 56 ____them in old age.
Several governments have___ 57 ____birth control policies in recent years. Among them are Japan, China, India and Egypt. In some cases the results have not been successful. Japan has been an___ 58____The Japanese adopted a birth control policy in 1921~3. People were___ 59 ____to limit their families. The birth rate fell from 34.3 per thousand per year to about 17.0 per year___ 60 ____ present.
________ 查看材料
A.Need
B.want
C.Absence
D.shortage
The source of the sun' s inconstancy is magnetism. Professor William Livingston has developed new theories about its magnetic nature.
"We don' t yet know what causes sun spots, "he says, "but we now think they ' re areas of high level magnetism that come up from the sun' s interior. So strong is their magnetic pull that the highly ionized gas nearby is not able to transmit energy out. "As a result these areas send out less heat and light and thus appear from Earth to be almost dark irregular surface patches.
Sun spot activity generally fluctuates in steady, 11-year cycled. Scientists have long formed the o pinion that as the size and number of sun spots increased, the overall energy sent out by the sun would de crease. Indeed, recent studies confirmed it, revealing that during peak periods of sun spot activity, the Earth experiences a small drop that can be seen clearly in received solar energy.
Could such a small drop in energy have an effect here on earth？ Perhaps some scientists think the world temperature could fall by' as much as 0.2 during periods of high solar magnetism.., enough to cause significant fluctuations in weather patterns.
According to the passage, it is believed that the sun ______ ．
A．moves in a quick but steady way year after year
B．sends out less and less heat and light with each passing year
C．radiates the same amount of light every year
D．might have a strong influence on the weather patterns
Questions 36 to 40 are based on the following passage:
W hat is the importance of the Afro American history to all Americans？ How could Afro Americans contribute anything to American history when they were just slaves and servants？ This is the image which many of us are taught when we go to school. This is the image many Afro Americans have of themselves also. The Afro Americans need to remake their real historical image so that it is known and accepted in its truthfulness by themselves and the rest of the world. Men and women of darker color are human beings entitled to respect and acceptance in history. When we think of famous scientists and inventors we immediately think of men such as Alexander Graham Bell, Thomas Edison and Jonas E.Salk. This is because we associate famous people with the Anglo Saxon race. But what about the Afro American inventors and scientists？ How many men during World War Ⅰ owe their lives to Garrett Morgan who invented the gas mask？ Garrett Morgan also invented the traffic light which saves numerous lives on our streets. Daniel Hale Williams was the first successful heart surgeon. Charles Drew saved hundreds of thousands of lives during World War II by his discovery of the ways and means of preserving blood plasma. Percy Julian has helped millions suffering from the excruciating pain of arthritis. These men and others should be as easily recognized as Bell, Edison and Salk.
America is made up of many different blends of cultures. These many cultures have come to enrich and diversify the American way of life. We should not think, because history has neglected to include the background of a particular culture, that these people have an inferior history. We should search for the truth and set the record straight against the slanders, the stereotyping and false images which have identified these people. We should understand each of the cultures and learn of their specific contribution to America's life story.
Only after we are taught the complete and accurate history of our great country and learn that the blending of cultures and backgrounds gives us ourstrength, can we go forward on the path to peace.
36. The function of the first paragraph is to ____.
A) present the main idea or the summary of the essay
B) present an introduction to the topic
C) provide background to the main theme
D) present many cultures have contributed to American history
37. Which of the following statements is true？
A) Graham Bell, T.Edison and J.E.Salk are not very important people.
B) Black people who contribute to society should have equal recognition with their white colleagues.
C) We should not associate famous people with the Anglo Saxon race only.
D) G.Morgan, D.H.Williams and Charles Drew were not Afro Americans.
38. Paragraph three tells us that ____.
A) we should oppose slander and stereotyping
B) the American way of life is richer because it is made up of many cultures
C) some cultures have been completely neglected
D) Afro Americans have an inferior history
39. The word “image” refers to ____.
A) picture B) portray C) impression D) similar
40. The main idea of the passage is ____.
A) There are many Afro Americans who are famous as scientists and inventors
B) Many Afro Americans have devoted to American history
C) Afro American experience to American history
D) Afro American history must be recognized as an important part of American history
Everybody may have seen the film "Death on the Nile (尼罗河) ," but nobody can imagine that the writer of the story, Agatha Christie, saved a baby in a most unusual way.
In June 1977, a baby girl became seriously ill in Deleville. Doctors there were unable to find out the cause of her illness, so she was sent to a famous hospital in London, where there were many excellent doctors. The baby was so seriously iii that a team of doctors hurried to examine her without any delay. The doctors, too, were puzzled by the baby's illness, and they also became discouraged. Just then a nurse asked to speak to them.
"I think the baby is suffering from thallium (铊) poisoning," said the nurse~ "A few days ago, I read a story 'A Pale Horse' written by Agatha Christie. Someone uses thallium poison, and all the symptoms (症状) are written in the book. They are exactly the same as the baby's."
"You're very good at observing things, "said a doctor, "and you may be right. We'll carry out some tests and find out whether the cause is thallium poisoning or not."
The tests proved that the baby had indeed been poisoned by thallium. Once they knew that cause, the doctors were able to give her correct treatment. The baby soon got well and was sent back to Deleville. A week later it was reported that the poison might have come from an insecticide (杀虫剂) used in Deleville.
The baby was sent to a hospital in London because ______.
A．her parents were living in London then
B．the hospitals in Deleville were full at that time
C．she was the daughter of a famous doctor in London
D．doctors in Deleville were not sure about the cause of her illness
Many things in nature, such as sunshine, temperature, and precipitation, affect climate. Nearness to mountain, oceans, and large lakes affects it loo. Another factor is altitude, or height above sea level. Air cools as altitude increases. So a city at a higher altitude may be colder than one at a lower altitude. Finally, winds affect climate. They move heat and moisture between the oceans and continents. Winds keep the tropics from overheating. They keep the polar regions from getting overly cold.
Climate changes over long periods of time. Some scientists think, for example, that the earth' s climate changed at the time of the dinosaurs. They think the dinosaurs died because of the change. What causes a climate to change？ One possible cause may be changes in the sun. Sunspots, for example, are cool, dark spots that form. on the sun. Sunspots may decrease precipitation on the earth and cause unusually dry periods. Changes in the atmosphere may change climate too. Volcanic eruptions, for instance, release solid particles into the air. These particles may form. a cloud that blocks out the sun ' s heat. Human activity is another cause of climate change. Air pollution and the reduction of forest cover may have long-term effects on climate.
This passage is concerned with things that affect______.
A．precipitation
B．climate
C．altitude
D．sunspots
