2. 职称英语
  3. Read the following passage. The Eocene epoch began 55 million years ago

Read the following passage. The Eocene epoch began 55 million years ago

游客2024-01-02  3
问题     Read the following passage.
    The Eocene epoch began 55 million years ago with a rapid increase in global temperatures, the Eocene warming. The warm period lasted for 20,000 years. It was so warm during this period that ocean water at the poles supported tropical life-forms. Climatologists have proposed several theories to explain the Eocene warming.
    Some scientists have hypothesized that changes in the ocean currents caused the warming. It is well documented that at the start of the Eocene many ocean currents drastically changed direction, perhaps because of a change in the position of the continents. Deep-water currents in the Atlantic Ocean, flowing in new directions, transported warm water from the tropics toward the poles. Proponents of the ocean current theory point to this change as the cause of the Eocene warming.
    A second theory proposes that an enormous comet struck Earth and initiated the Eocene warming. When comets strike Earth, they can create atmospheric conditions that lead to the increase in atmospheric temperatures. The comet theory is supported by the discovery of a high concentration of magnetic particles in a thick layer of clay that dates back to the beginning of the Eocene. Since comet collision often deposits magnetic particles in the soil, the clay layer provides good evidence for the comet theory.
    A third theory attributes the warming to the release of methane from oceans into the atmosphere. Substantial quantities of methane are usually trapped on the floor of the ocean. However, there is evidence that at the beginning of the Eocene, changes in the oceanic environment caused large portions of the methane to escape. Methane is a potent greenhouse gas, and once it escapes into the atmosphere, it can cause a rise of atmospheric temperatures and therefore, events such as the Eocene warming.
    Now listen to part of a lecture on the topic you just read about.
    Summarize the points made in the lecture, being sure to explain how they challenge the specific theories presented in the reading passage.
Unfortunately, none of the theories presented in the reading selection adequately explains the Eocene warming.
    First, about the warming effect of the change of ocean currents, it’s true that these changes would have caused some warming. However, we did some computer modeling of the currents. The computer models show that even when the ocean currents started flowing in new directions, they could still transport only a relatively limited amount of heat. The amount of heat they transported was much smaller than the amount of heat needed to cause the Eocene warming, so the ocean current theory does not seem to work.
    Second, the comet theory. At first, the clay layer with magnetic particles was thought to indicate a comet collision. However, new findings tell a different story. The magnetic particles in the clay did not come from a comet collision, but were actually produced by primitive one-celled organisms, a kind of bacteria. The magnetic particles were the only evidence for the comet hypothesis. Without that evidence, the comet theory collapses.
    As for the third theory about methane, the problem is timing. See, what the reading does not make clear is that after the oceanic methane starts escaping, it still takes thousands of years for it to build up in the atmosphere and create a greenhouse effect. So, we would expect that the atmospheric warming happened thousands of years after the methane started escaping, but that’s not what geological data show us. The data show that the climatic warming started happening at the same time as the escape of methane. Since the warming started at the same time and not thousands of years later, it could not have been caused by a slow accumulation of methane in the atmosphere.
选项
答案     The speaker introduces some new evidence and analyses on the Eocene wanning, and thereby disapproves of the three theories proposed in the reading.
    To begin with, the reading suggests that the warming was caused by the changed direction of ocean currents, which brought warm water from the tropics toward the poles and led to global warming. However, computer modeling of the currents revealed that the amount of heat transported by ocean currents was much smaller than the amount needed to cause the Eocene warming.
    The second theory contends that a comet collision at the beginning of the Eocene, evidenced by the discovery of a high concentration of magnetic particles in a thick layer of clay, led to a rise in the atmospheric temperatures. But new findings pointed out that those magnetic particles were produced by primitive one-celled organisms, not the strike. Thus, this theory is untenable.
    Finally, as claimed by the third theory, the methane releasing from oceans into the atmosphere may be responsible for the warming. Yet, the speaker expose the crucial vulnerability of the theory: the warming and the escape of methane happened simultaneously, and it actually takes thousands of years to create a greenhouse effect through the accumulation of methane, so the release of methane is not the culprit.
解析     题目：小孩(5到10岁)在学习数学、语言、科学和历史之余，还应学习艺术和音乐。
    本题是“Agree or Disagree”类型。文章应该首先表明态度，之后再对题目的两方面(即学习艺术和音乐或者不学)的利弊展开讨论，为自己所选择的态度提供论点支持。如果选择支持，则可以重点讨论学习艺术和音乐的益处；如果选择不支持，则多强调弊端。在重点阐述自己选择观点的理由时，还可以设想一下对立观点可能挑战所选观点的理由，并加以反驳，从而强调自己的观点。这样做还有一个好处。就是会使得段落衔接更加自然，而不是生硬地按顺序摆出理由。
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