[求助]補充250中的212,217,&220

補充250中的212,217,&220fficeffice" />

212. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.

(A) overtime that has the potential of causing

(B) overtime that has the potential to cause

(C) overtime that potentially can cause

(D) overtime, a practice that has the potential for causing

(E) overtime, a practice that can, potentially, cause

(E)為正確答案

但是can和potentially不是會重複表達嗎?那麼(C)錯為什麼(E)會對呢

217. Although some officials noted that using machines for farming in ffice:smarttags" />China costs more than traditional hand cultivation, the mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield while the previous year’s costs were cut in half.

(A) mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield while the previous year’s costs were cut in half

(B) mechanization of farming in the laceType>villagelaceType> of Long Bow doubled the corn yield while cutting costs to half those of the previous year

(C) mechanization of farming in the village of Long Bow doubled the corn yield as cost were cut to half of the previous year’s

(D) farming mechanization in the village of Long Bow doubled the corn yield as it cut in half the previous year’s costs

(E) farming mechanization in the village of Long Bow doubled the corn yield while costs were cut to half that of the previous year

             正確答案為(B),但是(D)為什麼不行呢??

             it可以指farming mechanization

             而farming mechanization cut in half the previous year’s costs 也很合理阿

220. Because Halley’s comet changes orbit slightly during the seventy-six-year interval between passing close to Earth, it may veer onto a collision course with a planet sometime in the distant future.

(A) between passing

(B) of passing

(C) between its passes

(D) of its passes

(E) as it passes

(C)為正確答案,(E)為什麼不行呢

it為Halley’s comet