OG 13th 42

GraceM

求问OG 13第42题

To develop more accurate population forecasts, demographershave to know a great deal more than now about the social and economicdeterminants 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 and economical
(C) would have to know a great deal more than they do now about the social and economical
(D) would have to know 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

答案选D
请问：OG解释"This sentence explains a hypothetical situation and therefore calls for a conditional or contrary-to-fact construction，because in order to more accurately predict population, demographers would have to know more than they presently know.可是感觉这里非要用挺奇怪的，如果把D想改成陈述语气（have to know a great deal more than they do now about the social and economic）还正确么？

DUKB24

嗯

还是正确的

zxppx

不需要想着怎么去把一个句子改得更好，只需要在五个选项中找出最合适的即可。E选项只要没问题就可以，为什么不可以用would have to? to develop表示的是目的，为了达到这个目的，demographers将要怎么样，用would have to正确！