The outer solar system.docx

托福模拟测试2014年2月21日 阅 读 第1篇Paragraph 1 1. The word innumerable in the passage is closest in meaning to_. A. varied B. indisputable C. individual D. Countless2. The authors description of the outer solar system in paragraph 1 mentions all of the following EXCEPT: A. The effect of the suns gravity on it is minimal. B. It exists beyond the orbits of the eight planets. C. It contains a great number of small frozen objects. D. Dwarf planets and their moons are located there.Paragraph 2:3. According to paragraph 2, which of the following is true of the Kuiper Belt?A. Some of the planets travel through it as they orbit the sun.B. There are many objects within it that revolve around the sun.C. It extends all the way out to sixty-eight AU from the sun.D. It covers an area spanning approximately 150 million kilometers.Paragraph 3:4. Why does the author mention Eris?A. To state that it is one of the five dwarf planets in the solar system.B. To claim that nothing else visible in the solar system is farther from the sun.C. To compare its characteristics with those of the known dwarf planets.D. To emphasize the number of years it takes to complete one orbit of the sun.5. The word it in the passage refers to_.A. the solar systemB. ErisC. sixty-three AUD. the sun6. According to paragraph 3, Pluto is currently closer to the sun than Neptune because_.A. the suns gravity has caused a permanent change in Plutos orbit.B. the elliptical orbit of Neptune has brought it into the outer solar systemC. it has an oval orbit that sometimes takes it into the inner solar system.D. it has an orbit that forces it to pass several of the planets in the solar system.7. In paragraph 3, the author implies that Ceres_.A. is the dwarf planet the most similar to MakemakeB. is large enough to be considered a planetC. is different from the other four dwarf planetsD. has a gravitational force stronger than PlutosParagraph 48. The authors description of the Kuiper Belt in paragraph 4 mentions which of the following?A. There are many comets that partially orbit the sun within it.B. There is enough material in it to create another planet.C. It contains more objects than the inner solar system.D. Comets are formed from the material that exists There.9. Look at the four squares that indicate where the following sentence could be added to the passage.For example, Halleys Comet takes seventy-five years to orbit the sun.Where would the sentence best fit?Paragraph 510. The word theoretically in the passage is closest in meaning to_.A. potentiallyB. supposedlyC. apparentlyD. definitely11. The word diverted in the passage is closest in meaning to _.A. extendedB. reconsideredC. redirectedD. distractedParagraph 612. In paragraph 6, the author discusses the Oort Cloud in order to_.A. argue that it is the outer limit of the solar system.B. propose the possibility that it does not exist.C. claim that humans have not been able to visit it.D. explain that very little is known about it yet.13. Directions: Select the appropriate statements from the answer choices and match them to the region of the outer solar system to which they relate. TWO of the answer choices will NOT be used. Answer ChoicesA. Lies adjacent to the inner solar system.B. Contains the eight planets as well as their moons.C. Is a theoretical place where comets are formed.D. Holds unused material from when the solar system formed.E. May extend tens of thousands of AU from the sun.F. Is the location of the asteroid belt.G. Presently contains three dwarf planets.Kuiper BeltOort CloudKey Words:1. celestial _2. realm_3. comet_4. gravitational _5. gravity _6. equivalent _7. dwarf _8. criteria _9. elliptical _10. an oval orbit _ The Outer Solar SystemParagraph 1 The inner solar system consists of the sun, eight planets, their moons, and the countless other celestial bodies that orbit the sun between the planets. There are also innumerable objects in the realm beyond the last planet in the region that has been termed the outer solar system. These objects include several dwarf planets and their moons, comets, and various small city and rocky objects that are too small to be classified as either.Paragraph 2 The boundary of the solar system in the limit of the suns gravitational pull since any objects that get caught by its gravity will begin to orbit the sun. So far, the most distant object discovered that orbits the sun is approximately sixty-eight astronomical units (AU) from the sun, yet some astronomers believe that the suns pull may extend even further than that. One AU is equivalent to the distance of Earth from the sun-roughly 150 million kilometers. Astronomers refer to the region of space where the majority of these faraway objects orbit the sun as the Kuiper Belt.Paragraph 3 The most distant visible object that is still a part of the solar system is Eris, the largest dwarf planet, which is sixty-three AU from the sun. It is so far from the sun that it completes a single orbit in 560 Earth years. Astronomers have thus far identified five dwarf planets, which have been given that moniker since they are large celestial objects that do not fit the criteria to be considered an actual planet. Pluto, which was once called the ninth planet, had its status downgraded to that of a dwarf planet in 2006 and belongs to the outer solar system. Yet Pluto is not always so distant from the sun, and its elliptical orbit at times-like the present-places it closer to the sun than Neptune, the farthest from the sun of the eight planets. Besides Pluto and Eris, the other dwarf planets are Ceres, Haumea, and Makemake. Ceres actually resides in the asteroid belt between Mars and Jupiter. Haumea, meanwhile, is approximately forty-three AU from the sun and completes a single orbit in 285 years while Makemake is around forty-six AU from the sun and takes 310 years to orbit it. Every distant dwarf planets is small, rocky, cold, and covered in frozen substances, most likely methane.Paragraph 4 Pluto, Haumea, and Makemake are all located wihin the Kuiper Belt. The Kuiper Belt, astronomers theorize, is a donut-shaped region between thirty and fifty AU from the sun. It contains around 70,000 objects, many of which are merely small icy bodies. Astronomers believe that they are the remains of the materials that were used during the creation of the solar system billions of years ago. Comets continually move into and out of the Kuiper Belt as they orbit the sun. Some of their orbits are very long and irregular, but others, such as Halleys Comet, engage in relatively short orbits that can be predicted with some regularity. Paragraph 5 As for Eris, it exists sightly outside of the Kuiper Belt although some astronomers claim it is located inside that area. Others, however, believe that Eris is in the Oort Cloud. This is a region that theoretically extends up to 50,000 AU from the sun. Its existence was first proposed by Dutch astronomer Jan Oort in the 1950s. Oort believed that all comets had to have originated from somewhere, so he theorized a region where they formed, were subsequently diverted from their courses by gravitational forces, and then moved into the inner solar system. The majority of objects that may be in the Oort Cloud are too small and distant to be seen with modern telescopes.Paragraph 6 In fact, the actual existence of the Oort Cloud is mostly based upon a theoretical belief since the long-term comets that orbits the sun must come from somewhere. Beyond the Oort Cloud lies the vast emptiness of space that leads to other stars located light years away from the solar system. How far past the Oort Cloud the suns gravitational pull extends is uncertain. It is a question that cannot be answered until modern science makes more technological advances.11. a donut-shaped region_12. orbit_13. theoretically_14. propose _15. subsequently_16. divert_17. potentially_18. apparently_19. extend_20. redir