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
答案 是E还是D哦?E里面 they do 能省略吗?各位帮忙确定一下哦 |