OG阅读详解.docVIP

THE ORIGINS OF CETACEANS Paragraph 1. Cetaceans are mammals. How walking mammal and swimming whale bridged? Fossils. Paragraph 2. discoveries -- reconstruct origins of cetaceans. Pakicetus. Paragraph 3. Pakicetus consists of skull of archaeocyte.? ?????????????????? transitional form between mammals, mesonuchids and cetaceans. ?????????????????? bred and gave birth on land. Paragraph 4. skeletons of Basilosaurus. 40 million years ago. 12million years after Pakicetus. ???????????????????????????????????????????????? fully marine whale. Paragraph 5. Ambulocetus natans. 49 million years ago. 3 million after Paki, 9 million before Basi ????????????????????????????????????????? on land and at sea. 1题： Their streamlined bodies, the abesence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land-dwelling mammals. 2题： However, unlike cases of sea otters..., it is not easy to evision what the first whales looked like. 注意，由于原文说是unlike，所以要将原文取非。 4题： The skull is ceteacean-like...。题干中的similar＝like，故定位此处。 7题： Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land. 8题： Basilosaurus was undoubtedly a fully marine whale. 10题： 简单来说，正确答案中的Although与原文中的even though逻辑关系一致。 DESERT FORMATION Paragraph 1: Desert increase. Paragraph 2: Desertification due to loss of vegetation and erosion of soil by wind and water Paragraph 3: reduction of vegetation - loss of soils ability to absorb water - loss soil - reduction of vegetation Paragraph 4: Desertifiction cause: trend to drier climatic conditions Paragraph 5: Desertification results from human activities: expanding population Paragraph 6: 4 major contributors: overcultivation, overgrazing, firewood gathering, overirrigation Paragraph 7-9: 具体讲以上因素。 Paragraph 10: Desertification results from vast land, people and difficulty of reversing or slowing process. ? 注：以下绿色字为题干关键词在原文中的定位词。红色字为答案出处。 2. Even in the areas that retain a soil cover, the reduction of vegetati