To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.
To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.
have to know a great deal more than now about the social and economic
have to know a great deal more than they do now about the social and economical
would have to know a great deal more than they do now about the social and economical
would have to know a great deal more than they do now about the social and economic
would have to know a great deal more than now about the social and economical
D is the correct answer
答案本身没问题,只是题外话想问一下,如果E改成 would have to know a great deal more than now about the social and economic,E是不是也正确。在下对于比较的省略这块语法点还不是很扎实,望NN指点。