無因就無果

  在假設題型里,如果想要找出段落推理的一個必要條件,那么我們首先就應明確,這個必要條件就是使得推理必然成立的一個假設,假設必為支持性假設。

  例:

  The population of peregrine falcons declined rapidly during the 1950’s and 1960’s and reached an all-time low in the early 1970’s. The decline was attributed by scientists to the widespread use of the pesticide DDT in rural areas

  Which of the following, if true, gives the strongest support to the scientists’ claim?

  (A) DDT was not generally in use in areas devoted to heavy industry

  (B) In the time since the use of DDT was banned in 1972, the population of peregrine falcons has been steadily increasing

  (C) Peregrine falcons, like other birds of prey, abandon eggs that have fallen out of the nest, even if the eggs remain intact

  (D) Starlings, house sparrows, and blue jays-birds the peregrine falcon preys on were not adversely affected by DDT in their habitats

  (E) Other birds of prey, such as the osprey, the bald eagle, and the brown pelican, are found in the same areas as is the peregrine falcon.

  題干是由果推因,游隼數(shù)量下降由使用殺蟲劑(DDT)所致,我們不妨將“游隼數(shù)量下降”視為B, 而將“使用DDT”視為A, 如果由B→A正確,那么我們就可以得出沒有A就不會存在現(xiàn)在的B,因此我們就可以推斷兩種情況,DDT禁用前與DDT禁用后游隼在數(shù)量上的比較,如果在 DDT禁用后,游隼數(shù)量開始增加的話,那么我們就會非??隙ǖ氖谴_實是殺蟲劑的使用導致了游隼數(shù)量的減少。這種類型的題目出錯的主要原因有兩點:一:考生無法把握題干要求,在段落內容之外進行推理;二:無法將題干給出的原因視做唯一原因。

  建議:

  考生應能在平時的不斷練習的過程中,學習找出論點和結論的能力,并依據(jù)兩者的關系進行判斷,只要弄清論點和結論也就相當于找出了答案。在實踐練習中,考生也應善于從題干所描述的對象中找出核心關鍵詞語,一般來講,我們可以通過在選項中加入Not 來判斷推理成立的有效性并排除那些誤選項。