改错题 7.The World Wildlife Fund has declared that global warming, a phenomenon that most scientists agree is caused by human beings' burning of fossil fuels, will create havoc among migratory birds by harming their habitats as a result of altering the environment.

A、 by harming their habitats as a result of altering the environment
B、 by altering the environment to the extent of it harming their habitats
C、 by altering the environment in ways harmful to their habitats
D、 from the fact that their habitats will be harmed by the environment being altered
E、 from the fact that the environment will be altered and this will harm their habitats

【正确答案】 C

【答案解析】Logical predication; Rhetorical construction
The sentence describes a declaration by the World Wildlife Fund that global warming will "create havoc" among migratory birds in certain respects, which are specified in the underlined portion. The underlined portion thus needs to specify, in a clear and focused fashion, how, according to the World Wildlife Fund, global warming will create havoc for the birds.
A The description in this option of the effects of global warming among migratory birds is convoluted and confusing. First, the sentence as written does not specify who or what is altering the environment. Second, given the reasonable guess that it is global warming that is or will harm the environment, the order of the listing of the causal elements is confusing. According to the sentence, global warming will alter the environment and then this altering will harm the habitat of birds. However, although this sentence accurately describes what causes what, the elements are listed in an order that does not correspond to the order of causation ("global warming" is followed by "harming the habitats," which is followed by "altering the environment").
B This sentence uses the word extent, followed by a condition, it harming their habitats, intended to imply a certain level of extent. The extent is great enough to harm the habitat of the birds. However, as worded, the sentence does not provide a clear condition on the level of extent. For example, in it harming their habitat, it is not clear what it refers to. The word it could refer to the environment or to the extent of change to the environment.
C Correct. This sentence clearly specifies how global warming will "create havoc" for the birds.
D This sentence, like sentence A, is convoluted and confusing, in part because, when reading the sentence, it is unnecessarily difficult to understand what is supposed to be causing what. Note that, although the meaning of this option is more or less the same as that of sentence C, this sentence, sentence D, is much more difficult to process.
E This sentence is unnecessarily wordy and difficult to process. Sentence C is a much better choice.
The correct answer is C.