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Passage 2 When Jules Verne wrote Journey to the Center of the Earth in 1864, there were many conflicting theories about the nature of the Earth’ s interior. Some geologists thought that it contained a highly compressed ball of incandescent gas, while others suspected that it consisted of separate shells, each made of different materials. Today well over a century later, there is little direct evidence of what lies beneath our feet. Most of our knowledge of the Earth’ s interior comes not from mines or boreholes, but from the study of seismic waves--powerful pulses of energy released by earthquakes. The way that seismic waves travel shows that the Earth’ s interior is far from uniform. The continents and the seabed are formed by the crust--a thin sphere of relatively light, solid rock. Beneath the crust lies the mantle, a different layer that extends approximately halfway to the Earth’ s center. There the rock is the subject of a battle between increasing heat and growing pressure. In its high levels, the mantle is relatively cool; at greater depths, high temperatures make the rock behave more like a liquid than a solid. Deeper still, the pressure is even more intense, preventing the rock from melting in spite of a higher temperature. Beyond a depth of around 2,900 kilometers, a great change takes place and the mantle gives way to the core. Some seismic waves cannot pass through the core and others are bent by it. From this and other evidence, geologists conclude that the outer core is probably liquid, with a solid center. It is almost certainly made of iron, mixed with smaller amounts of other elements such as nickel. The conditions in the Earth’ s core make it a far more alien world than space. Its solid iron heart is subjected to unimaginable pressure and has a temperature of about 9,000°F. Although scientists can speculate about its nature, neither humans nor machines will ever be able to visit it. The word "There", the first word in the last sentence of paragraph 2 refers to which of the following
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Questions 14-16 are based on the following passage. You now have 15 seconds to read questions 14-16. From this selection it seems true that the Atlantic ocean ______ .
法律和党的政策最主要的区别在于前者具有规范性，后者不具有规范性。 ( )
共同犯罪指二人以上共同故意犯罪。 ( )
Passage 3 Most scientists blame people, at least in part, for global warming. Now, some researchers say people may be partly to blame for the cooling of Antarctica as well. While average global temperatures have risen about one degree Fahrenheit over the past century, Antarctica over all appears to have cooled slightly in the past few decades. That has been puzzling, because the polar regions are thought to be more sensitive to warming trends than the rest of the globe. Even more puzzling, a small portion of Antarctica--the peninsula that stretches north toward South America--defies the cooling trend. It has been warming very rapidly, about five degrees over the past 50 years, 10 times the global average. Writing in today’ s issue of the journal Science, Dr. David Thompson, a professor of atmospheric science at Colorado State University, and Dr. Susan Solomon, a senior scientist at the National Oceanic and Atmospheric Administration in Boulder, Colo., argue that the ozone hole, which has opened up each spring over Antarctica in recent years, may help explain both contradictory trends. A vortex of winds continually blows around Antarctica, tending to trap cold air at the South Pole. In the new paper, Dr. Thompson and Dr. Solomon show that the winds have strengthened in the past few decades, keeping the cold air even more confined. The peninsula, which lies outside the wind vortex, escapes the cooling effect, the scientists said. They say the ozone hole may be the cause of the stronger winds. Close to the ground, ozone, a molecule consisting of three oxygen atoms, forms a large and unhealthy component of smog. High in the atmosphere, however, nature occurring ozone is essential for life, blocking ultraviolet rays that would fatally mangle DNA. However, fewer ozone molecules mean the atmosphere absorbs less ultraviolet radiation. Instead of warming the air, the rays bounce off the snow and ice of Antarctica and reflect back into space. Scientists already knew that the ozone hole had cooled the upper atmosphere. Dr. Thompson and Dr. Solomon show that the troposphere, the lowest six miles of the atmosphere, has also cooled. "It’ s a lot of food for thought in there," said Dr. John Walsh, a professor of atmospheric science at the University of Illinois and an author of a paper in Science in January that indicated Antarctica was cooling. He noted that the ozone hole was usually largest in November or December, but that the greatest cooling had been about six months later. The author of the passage is mainly concerned with ______ .
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