To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.
Hi mike, thank you for the explanation. I would like to know the explanation for one more ambiguity in my mind that's about the tense"would have to know". According to your conditional video in the magoosh tutorials " would have to knw" comes under second conditional which is not the case here. Instead why is "will have to know" not correct?
Great question, Rahul. The answer is that this sentence really is a second conditional sentence, in terms of meaning. "To develop" at the beginning of the sentence is short for "IN ORDER to develop," which could also be expressed as "IF THEY WERE to develop." In other words, this sentence is proposing a second conditional situation-- an unreal situation where demographers would be able to develop more accurate population forecasts, conditional on demographers gaining new knowledge that they don't have right now.
1 Explanation