GWD-1-Q32请高手指点

To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

1. have to know a great deal more than now about the social and economic
2. have to know a great deal more than they do now about the social and economical
3. would have to know a great deal more than they do now about the social and economical
4. would have to know a great deal more than they do now about the social and economic
5. would have to know a great deal more than now about the social and economical

   i think the correct one is D but the answer is E .confusing...

请列出题号. 便大家搜寻. thank you

go with D

1.economical的意思是节约,所以不对. B CE 错

2.最好用 would表示与现实相反.因为现在并没有"more accurate". 然后than后面,因为auxiliary verb的时态不一致,一个是would 一个是 do 所以不能省略,要补出do 来...所以A 错

D对!

LZ以后记得发题号，我已经帮你把题目改了。

这题答案就是D的