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新gre逻辑阅读 每日一练2

发布时间:2016-03-01  编辑:查字典英语网小编

  新gre考试实施以来,参加了新版gre考试的考生都觉得阅读部分的题难度增加了,这主要是由于新gre考试逻辑阅读需要考生的逻辑反应一定要比以前更快,可能考生还是有点不习惯,或是没有准备充足。那么,接下来的几天,小编将给大家搜索整理一些新gre考试逻辑阅读的练习题,希望考生能从平日的练习中总结规律,找到解题技巧。

  Many theories have been formulated to explain the

  role of grazers such as zooplankton in controlling the

  amount of planktonic algae in lakes.

  The first theories of such grazer control were merely

  5 based on observations of negative correlations

  between algal and zooplankton numbers. A low number

  of algal cells in the presence of a high number of

  grazers suggested, but did not prove, that the grazers

  had removed most of the algae. The converse obser-

  10 vation, of the absence of grazers in areas of high

  phytoplankton concentration, led Hardy to propose

  his principle of animal exclusion, which hypothe-

  sized that phytoplankton produced a repellent that

  excluded grazers from regions of high phytoplankton

  15 concentration. This was the first suggestion of algal

  defenses against grazing.获得更多gre考试咨询点击进入免费咨询顾问或联系QQ客服:800004500

  Perhaps the fact that many of these first studies

  considered only algae of a size that could be collected

  in a net , a practice that over-

  20 looked the smaller phytoplankton

  that we now know grazers are most likely to feed on,

  led to a de-emphasis of the role of grazers in subse-

  quent research. Increasingly, as in the individual

  studies of Lund, Round, and Reynolds, researchers

  25 began to stress the importance of environmental

  factors such as temperature, light, and water move-

  ments in controlling algal numbers. These environ-

  mental factors were amenable to field monitoring and

  to simulation in the laboratory. Grazing was believed

  30 to have some effect on algal numbers, especially after

  phytoplankton growth rates declined at the end of

  bloom periods, but grazing was considered a minor

  component of models that predicted algal population

  dynamics.

  35 The potential magnitude of grazing pressure on

  freshwater phytoplankton has only recently been

  determined empirically. Studies by Hargrave and

  Geen estimated natural community grazing rates by

  measuring feeding rates of individual zooplankton

  40 species in the laboratory and then computing com-

  munity grazing rates for field conditions using the

  known population density of grazers. The high esti-

  mates of grazing pressure postulated by these

  researchers were not fully accepted, however, until the

  45 grazing rates of zooplankton were determined directly

  in the field, by means of new experimental techniques.

  Using a specially prepared feeding chamber, Haney

  was able to record zooplankton grazing rates in natural

  field conditions. In the periods of peak zooplankton

  50 abundance, that is, in the late spring and in the summer,

  Haney recorded maximum daily community grazing rates,

  for nutrient-poor lakes and bog lakes, respectively, of 6.6

  percent and 114 percent of daily phytoplankton production.

  Cladocerans had higher grazing rates than

  55 copepods, usually accounting for 80 percent of the

  community grazing rate. These rates varied seasonally,

  reaching the lowest point in the winter and early spring.

  Haneys thorough research provides convincing field

  evidence that grazers can exert significant pressure on

  60 phytoplankton population.

  

  1. It can be inferred from the passage that the first theories of

  grazer control mentioned in the first paragraph would have been

  more convincing if researchers had been able to

   observe high phytoplankton numbers under

  natural lake conditions

   discover negative correlations between

  algae and zooplankton numbers from their

  field research

   understand the central importance of

  environmental factors in controlling the

  growth rates of phytoplankton

   make verifiable correlations of cause and

  effect between zooplankton and

  phytoplankton numbers

   invent laboratory techniques that would

  have allowed them to bypass their field

  research concerning grazer control

  2. Which of the following, if true, would call into

  question Hardys principle of animal exclusion?

   Zooplankton are not the only organisms

  that are affected by phytoplankton

  repellents.

   Zooplankton exclusion is unrelated to

  phytoplankton population density.

   Zooplankton population density is higher

  during some parts of the year than during

  others.

   Net phytoplankton are more likely to

  exclude zooplankton than are

  nannoplankton.

   Phytoplankton numbers can be strongly

  affected by environmental factors.

  For the following question, consider each of the choices separately and select all that apply

  3. The author would be likely to agree with

  which of the following statements regarding

  the pressure of grazers on phytoplankton

  numbers?

  □A Grazing pressure can vary according to the

  individual type of zooplankton.

  □B Grazing pressure can be lower in nutrient-poor lakes

  than in bog lakes.

  □C Grazing tends to exert about the same

  pressure as does temperature.

  4. It can be inferred from the passage that one way

  in which many of the early researchers on grazer

  control could have improved their data would

  have been to

   emphasize the effects of temperature, rather

  than of light, on phytoplankton

   disregard nannoplankton in their analysis of

  phytoplankton numbers

   collect phytoplankton of all sizes before

  analyzing the extent of phytoplankton

  concentration

   recognize that phytoplankton other than net

  phytoplankton could be collected in a net

   understand the crucial significance of net

  phytoplankton in the diet of zooplankton

  5. According to the passage, Hargrave and Geen

  did which of the following in their experiments?

   They compared the grazing rates of

  individual zooplankton species in the

  laboratory with the natural grazing rates

  of these species.

   The hypothesized about the population

  density of grazers in natural habitats by

  using data concerning the population

  density of grazers in the laboratory.

   They estimated the community grazing rates

  of zooplankton in the laboratory by using

  data concerning the natural community

  grazing rates of zooplankton.

   They estimated the natural community

  grazing rates of zooplankton by using

  data concerning the known population

  density of phytoplankton.

   They estimated the natural community

  grazing rates of zooplankton by using

  laboratory data concerning the grazing

  rates of individual zooplankton species.

  答案: D/B/AB/C/E

  以上即是阅读练习题,对于新gre考试逻辑阅读,考生除了采取题海战术,其实更应该做的就是总结。如果能从平日的练习中找到解新gre考试逻辑阅读题的思路,那么,要比采取题海战术更好。

  

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