Sentence Correction

To develop more accurate population forecasts, demographers have to know a great deal more than now about 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 that they do now about 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 economical
[spoiler]Answer E

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I got the answer as C, considering the comparison rules. Please share your thoughts

i like D

A. improper comparison between demographers' knowledge and now

D. correct IMO. social and economic gels well. economic: to do with the economy. also properly compares demographers knowledge in future to knowledge now

B, C and E out because economical means cheap and doesnt fit in.


hey rahcool4u,
whats the source?

scoobydooby wrote:i like D

A. improper comparison between demographers' knowledge and now

D. correct IMO. social and economic gels well. economic: to do with the economy. also properly compares demographers knowledge in future to knowledge now

B, C and E out because economical means cheap and doesnt fit in.


hey rahcool4u,
whats the source?

I definitely think D is the answer.

"...more than they do now..." is required to complete the comparison.

I agree with the reasons above that "economic" is also correct here.

Somebody please explain me why should we insert "would" in this case? For me, the structure without "would" is less wordier and does not change the meaning.

got the question from GMAT paper sets ( 20) . Take a look at the attachment.