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How many Earths could fit inside the Sun？A．One million.B．93 million.C．Two million.D．100 mi

How many Earths could fit inside the Sun？

A．One million.

B．93 million.

C．Two million.

D．100 million.

答案

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发布时间：2020-07-14

更多“How many Earths could fit inside the Sun？A．One million.B．93 million.C．Two million.D．100 mi”相关的问题

第1题

In May 1989, space shuttle "Atlantis" released in outer space the space probe "Megal-lan",

which is now on her 15-month and one-billion-kilometer flight to Venus. A new phase in space exploration has begun. The planet Venus is only slightly smaller than the earth; it is the only other object in the solar system, in fact, that even comes close to the earths size. Venus has a similar density, so it is probably made of approximately the same stuff, and it has an atmosphere, complete with clouds. It is also the closest planet to the earth, and thus the most similar in distance from the sun. In short, Venus seems to justify its long-held nickname of "the earths twin". The surface temperature of Venus reaches some 900 degree F. Added to that is an atmospheric pressure about 90 times the earths. High overhead in the carbon dioxide(CO2)that passes for air is a layer of clouds, perhaps 10 to 20 miles thick, whose little drops consist mostly of sulfuric acid(H2SO4). Water is all but nonexistent. Born with so many fundamental similarities to the earth, how did Venus get to be so radically different？ It is not just an academic matter. For all its extremes, Venus is a valuable laboratory for researchers studying the weather and climate of the earth. It has no the earths oceans, so the heat-transport and other mechanisms are greatly simplified. In addition, the planet Venus takes 243 earth-days to turn once on its axis, so incoming heat from the sun is added and distributed at a more leisurely, observable pace. Question: The main idea of this passage is about______.

A．problems of space travel

B．scientific methods in space exploration

C．the importance of Venus to the earth

D．conditions on Venus

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第2题

请根据短文内容，回答题。 So Many "Earths"The Milky Way （银河) contains billions of

请根据短文内容，回答题。

So Many "Earths"

The Milky Way (银河) contains billions of Earth-sized planets that could support life. That&39;s the finding of a new study. It draws on data that came from NASA&39;s top planet-hunting telescope.＜br＞

A mechanical failure recently put that Kepter space telescope out of service..Kepler had played a big role in creating a census of planets orbiting some 170,000 stars. Its date have been helping astronomers predict how common planets are in our galaxy. The telescope focused on hunting planets that might have conditions similar to those on Earth.＜br＞

The authors of a study published in The Proceedings of the National Academy of Sciences conclude that between 14 and 30 out of every 100 stars with a mass and temperature similar to the Sun may host a planet that could support life as we know it. Such a planet would have a diameter at least as large as Earth&39;s but no more than twice that big. The planet also would have to orbit in a star&39;s habitable zone. That&39;s where the surface temperature would allow any water to exist as liquid.＜br＞

The new estimate of how many planets might fit these conditions comes from studying more that 42,000 stars and identifying suitable worlds orbiting them. The scientists used those numbers to extrapolate (推算) to the rest of the stars that the telescope could not see.＜br＞

The estimate is rough, the authors admit. If applied to the solar system, it would define as habitable a zone starting as close to the Sun as Venus and running to as far away as Mars. Neither planet is Earthlike (although either might have been in the distant past). Using tighter limits, the researchers estimate that between 4 and 8 out of every 100 sunlike stars could host an Earth-sized world. These are ones that would take 200 to 400 days to complete a yearly orbit.＜br＞

Four out of every 100 sunlike stars doesn&39;t sound like a big number. It would mean, however, that the Milky Way could host more than a billion Earth-sized planets with a chance for life

The Kepler space telescope has been in service for 15 years. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第3题

The groundwater system is similar to a river system. Therefore, instead of having channel

s that 【M1】______ connect different parts of the drainage basin, the groundwater system has connecting pores. Some soils and rock have connecting pores where water can move 【M2】______ through. Soils and rock are permeable and water can 【M3】______ pass through them this way. Sandstone is a common permeable rock. Soil or rock that have many large connected pores 【M4】______ is very permeable. Water can pass through it easily. Soil or rock that has few or small pores is not permeable 【M5】______ because water cant easily pass through. Some material, such as clay, has very small pores or no pores at all. Water cant pass through this impermeable material. How deep into Earths crust do you suppose groundwater can go？ That depends on the permeability of soil and rock. Groundwater will keep going to lower 【M6】______ elevations until it reaches a lay of impermeable rock. 【M7】______ When this happens, the impermeable rock acts like a dam and the water cant move down any deep. So, it 【M8】______ begins filling up the pores in the rocks over the 【M9】______ impermeable layer. A layer of permeable rock that transmits water freely is an aquifer. The area where all of the pores in the rock are completely filled in water is 【M10】______ the zone of saturation. The upper surface of this zone is the water table.

【M1】

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第4题

The northern and southern polar regions are different in many ways. The most important dif

ference concerns the distribution of land and water. The northern Arctic regions are ice-covered sea, almost completely surrounded by land. The pole itself is in deep water. In the south, Antarctic is a huge continent which is surrounded by a great ocean. Because of this basic difference other differences occur. The Arctic has a varied climate, while the Antarctic climate varies little; the Arctic has much plant life, but the Antarctic is an empty desert. And whereas the Arctic has been exploited economically for centuries, trade has never really touched Antarctic. Interest in the Arctic began when America was discovered, and explorers tried to find a western sea route to India and China. In their search to find the "North-West Passage" the main problem facing the explorers was how to avoid the ice. One explorer, Nansen, found a unique answer to this problem. He intentionally became struck in the ice and traveled with it across the Arctic Ocean! But although many explorers tried, it was not until 1903 that the Arctic polar region was crossed by sea. Antarctic exploration begins with Ptolemy. He believed that all the oceans were surrounded by land, and therefore, there was huge continent somewhere in the south. His idea led to centuries of search, and again trade played its part. The real discoverers of Antarctic were the hunters who traveled far south to catch seals. One reason for the present interest in both polar regions is that world may soon be short of fresh water. In fact, over 85% of the earths entire fresh water is found in the polar ice. If we could find a way of carrying this ice to other parts of the world, this would solve all our fresh water problems.

Trade, according to the passage, has never really touched Antarctic because Antarctic is

A．a land surrounded by a great ocean

B．an empty desert and has no plant life

C．not open to public

D．different from the Arctic

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第5题

The relative roles that abiotic and biotic factors play in the distribution of organisms i

s especially important now, when the world is confronted with the consequences of a growing human population. Changes in climate, land use, and habitat destruction are currently causing dramatic decreases in biodiversity throughout the world. An understanding of climate-organism relationships is essential to efforts to preserve and manage Earths biodiversity.

The authors main purpose in paragraph 5 is to

A．explain the process of studying organism responses to climate change

B．stress the importance of learning how climate affects plants and animals

C．illustrate an important point about factors affecting biodiversity

D．examine current research practices on the distribution of organisms on Earth

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第6题

As he collected fossils from strata throughout England, Smith began to see that the fossil

s told a different story from the rocks. Particularly in the younger strata, the rocks were often so similar that he had trouble distinguishing the strata, but he never had trouble telling the fossils apart. While rock between two consistent strata might in one place be shale and in another sandstone, the fossils in that shale or sandstone were always the same. Some fossils endured through so many millions of years that they appear in many strata, but others occur only in a few strata, and a few species had their births and extinctions within one particular stratum. Fossils are thus identifying markers for particular periods in Earths history.

The word "virtually" in the passage is closest in meaning to

A．possibly

B．absolutely

C．surprisingly

D．nearly

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第7题

The salinity of the earths oceans is about______.A．thirty-five part per thousandB．thirty-f

The salinity of the earths oceans is about______.

A．thirty-five part per thousand

B．thirty-five parts per thousand

C．thirty-five of thousand

D．thirty-five out of thousand

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第8题

More people die of tuberculosis（结核病)than of any other disease caused by a single agen

More people die of tuberculosis(结核病)than of any other disease caused by a single agent. This has probably been the case in quite a while. During the early stages of the【M1】______ industrial revolution, perhaps one in every seventh deaths in【M2】______ Europes crowded cities were caused by the disease. From【M3】______ now on, though, western eyes, missing the global picture, saw the【M4】______ trouble going into decline. With occasional breaks for war, the rates of death and infection in the Europe and America dropped steadily【M5】______ through the 19th and 20th Centuries. In the 1950s,the introduction of antibiotics strengthened the trend in rich countries, and the antibiotics were allowed to be imported to poor countries. Medical researchers【M6】______ declared victory and withdrew. They are wrong. In the mid-1980s the frequency of infections【M7】______ and deaths started to pick up again around the world. Where tuberculosis vanished, it came back; in many places where it had【M8】______ never been away, it grew better. The World Heath Organization【M9】______ estimates that 1.7 billion people(a third of the earths population) suffer from tuberculosis. Even when the infection rate was falling, population growth kept the number of clinical cases more or less constantly at 8 million a year. Around 3 million of those people【M10】______ died, nearly all of them in poor countries.

【M1】

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第9题

听力原文： Spaceships travel around the earth, go to the moon, and return home safely. T

he astronauts carry important supplies with them on the spaceship — food, water and air. Sometimes there are problems on the spaceship, and the astronauts have to understand how the spaceship works in order to repair the problems. In a way, all of us are really on a spaceship, the planet Earth. We move around the Sun at 18 miles per second and never stop. On our spaceship we have four billion people and a limited supply of air, water and land. These supplies, just like the limited supplies on the astronauts spaceship, have to be used carefully because we cant buy new air, water or land from anywhere else. Everyone needs air, water and land to live — this is our environment. The environment on our planet is a closed system; nothing new is ever added. Nature recycles its resources. Water, for example, evaporates and rises to form. clouds. This same water returns to the earth as rain or snow. The rain that falls today is actually the same water that fell on the dinosaurs 70 million years ago. Over the years, people have changed the environment. We have poured back into the land, air, and water more wastes than nature can clean. So we have pollution today. To continue to survive, we must learn how to use the Earths resources wisely, without destroying them. To save the spaceship Earth, we must cooperate with nature and learn better ways to use, not to abuse our environment. Questions 20 to 22 are based on the passage you have just heard. 20. Which would be the best title for the passage？ 21. Which is true according to the passage？ 22. What can we conclude from the passage？20．

A．The present population on earth is fourteen billion.

B．Water is recycled every seventy million years.

C．The planet earth travels around the sun at 18 miles per second.

D．The earth is compared to a spaceship because they both travel around the sun.

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第10题

How many types can the packing be classified into？

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