2017託福閱讀理解考前衝刺題及答案
導語:閱讀理解是根據文章內容,找出答案的一種題目,下面是YJBYS小編提供的2017託福閱讀理解考前衝刺題,做完記得對答案哦!
Generally, in order to be preserved in the fossil record, organisms must possess hard body parts such as shells or bones. Soft, fleshy structures are quickly destroyed by predators or decayed by bacteria. Even hard parts left on the surface for a certain length of time will be destroyed. Therefore, organisms must be buried rapidly to escape destruction by the elements and to be protected against agents of weathering and erosion. Marine organisms thus are better candidates for fossilization than those living on the land because the ocean is typically the site of sedimentation, whereas the land is largely the site of erosion.
The beds of ancient lakes were also excellent sites for rapid burial of skeletal remains of freshwater organisms and skeletons of other animals, including those of early humans. Ancient swamps were particularly plentiful with prolific growths of vegetation, which fossilized in abundance. Many animals became trapped in bogs overgrown by vegetation. The environment of the swamps kept bacterial decay to a minimum, which greatly aided in the preservation of plants and animals. The rapidly accumulating sediments in flood plains, deltas, and stream channels buried freshwater organisms, along with other plants and animals that happened to fall into the water.
Only a small fraction of all the organisms that have ever lived are preserved as fossils. Normally, the remains of a plant or animal are completely destroyed through predation and decay. Although it seems that fossilization is common for some organisms, for others it is almost impossible. For the most part, the remains of organisms are recycled in the earth, which is fortunate because otherwise soil and water would soon become depleted of essential nutrients. Also, most of the fossils exposed on Earth's surface are destroyed by weathering processes. This makes for an incomplete fossil record with poor or no representation of certain species.
The best fossils are those composed of unaltered remains. Generally, it is the inorganic hard parts, composed mostly of calcium carbonate, that form the vast majority of unaltered fossils. Calcite and aragonite also contributed to a substantial number of fossils of certain organisms.
1. According to the passage , an organism without hard body parts
(A) is not likely to appear in the fossil record
(B) is not heavy enough to sink below the surface
(C) is not attractive to predators
(D) takes a long time to decay
2. The word "agents" in line 5 is closest in meaning to
(A) dangers
(B) examples
(C) areas
(D) causes
3. Why are marine organisms good candidates for fossilization?
(A) They have more fleshy structures than land organisms.
(B) It is likely that they will be buried rapidly.
(C) The water environment speeds the decay caused by bacteria.
(D) It takes longer for them to be preserved.
4. The fact that the "land is largely the site of erosion" (line 7 - 8) is significant because
(A) erosion is less destructive than sedimentation.
(B) fossils are most common in areas subject to erosion.
(C) erosion contributes to the destruction of skeletal remains.
(D) few organisms live in areas that experience extensive erosion.
5. According to the passage , why were the remains of organisms trapped in swamps better preserved for the fossil record than those that were not?
(A) The swamp environment reduced the amount of bacterial decay.
(B) Swamp waters contained higher amounts of materials such as calcium carbonate.
(C) There were fewer sediments in swamps than in other bodies of water.
(D) Swamp vegetation accelerated the decomposition of organisms.
6. The word "aided" in line 13 is closest in meaning to
(A) reversed
(B) helped
(C) reformed
(D) counted
7. It can be inferred that flood plains, deltas, and stream channels (lines 14 - 15) are similar in which of the following ways?
(A) Animals rather than plants have been preserved at such locations.
(B) Such locations are likely to be rich sources of fossils.
(C) Fossilized human remains are only rarely found in such locations.
(D) Rapid sedimentation in such locations makes it difficult to locate fossils.
8. What is the author's main point in paragraph 3?
(A) Weathering makes it impossible to identify many fossils.
(B) Many fossils have been buried forever under the soil.
(C) Fossils provide a limited sample of ancient organisms.
(D) It is easier to find the remains of plants than animals.
9. Why does the author mention "aragonite" in line 27
(A) To explain why fossils are rare
(B) To compare aragonite fossils and calcite fossils
(C) To argue that certain fossils are more informative than others
(D) To illustrate the kinds of inorganic hard parts that can form fossils
參考答案:CADAD ACBD
相關文章
-
2016年託福閱讀理解衝刺練習題及答案
text 1Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mechanisms designed to frustrate the potential colonists. These ca -
2017托福考試閱讀模擬衝刺題及答案
導語:模擬衝刺題一般出題都是很有針對性的,所以大家在最後階段要多做哦。In 1900 the United States had only three cities with more than a million residents — New York, Chicago, and Philadelphia. By 193 -
2017下半年公共英語三級閱讀理解考前衝刺題及答案
導語:閱讀理解是根據文章內容找出答案的一種題目,下面是YJBYS小編提供的2017下半年公共英語三級閱讀理解考前衝刺題,做完記得對答案哦!Fifteen years ago, I entered the Boston Globe, which was a temple to me then. -
託福閱讀理解衝刺題2017
心態要祥和,銷售傳福音,服務獻愛心,下面是本站小編爲你們整理的內容,希望你們喜歡。銷售競賽口號1. 因爲有緣我們相聚,成功靠大家努力2. 風險越大,銷售員越不願意拜訪客戶3. 銷售的第二步就是把自己銷售給自己4. 銷售永遠是 -
2017托福考試閱讀模擬衝刺題帶答案
導語:在最後階段,多做模擬衝刺題,可以很好的'把握出題方向哦。下面是YJBYS小編提供的2017托福考試閱讀模擬衝刺題,做完記得對答案哦!The Arts and Crafts Movement in the United States was responsible for sweeping c -
2017下半年托福考試閱讀理解模擬衝刺題
導語:閱讀理解是托福考試中篇幅最長的`,但是它並沒有想象中可怕,下面是YJBYS小編提供的2017下半年托福考試閱讀理解模擬衝刺題,做完記得對答案哦!Pheromones are substances that serve as chemical signals between memb -
2017托福考試閱讀理解模擬題及答案
模擬題是根據真正的`考試試題模仿出來的試題,這樣的練習對考試很有幫助。下面是小編整理的2017托福考試閱讀理解模擬題及答案,希望對大家有用,更多消息請關注應屆畢業生網。According to some scientists, migratory bir -
2017年托福考試閱讀理解模擬題及答案
考試的通過離不開大量的習題練習,習題練習的過程可以加深對知識點的記憶。以下本站小編整理的2017年托福考試閱讀理解模擬題及答案,歡迎閱讀練習,更多信息請關注應屆畢業生網! The iPhone: What the Critics SayBosto -
2017年公共英語二級閱讀理解考前衝刺題及譯文詳解
導語:閱讀理解是公共英語當中篇幅比較大的一種題型,下面是YJBYS小編提供的2017年公共英語二級閱讀理解考前衝刺題及譯文詳解,做完記得對答案哦!There is distinction between reading for information and reading for u -
2017年9月公共英語一級閱讀理解考前衝刺題及詳解
導語:閱讀理解是公共英語當中最多單詞的一種題型,很多考生望而生畏,但其實不然,多做練習題你就知道了。 題一President Arling has put his long awaited economic restructuring program before the Congress. It pro