To develop more accuratepopulation forecasts, demographers have to know a great deal more than nowabout the social and economic determinants of fertility.
A. have to know a great deal more than now about the social and economic
B. have to know a great deal more than they do now about the social andeconomical
C. would have to know a great deal more than they do now about the social andeconomical
D. would have toknow a great deal more than they do now about the social and economic E. would have to know a great deal more than now about the social and economic
在prep 一题中,我曾问过类似的问题,其中一个解答是,如果要省略一起省略,要么都补出。
为什么这题不能全部省略呢?
附上上次的链接:
PREP 比较中省略问题 求解答
http://forum.chasedream.com/foru ... &fromuid=993387
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