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 than they do now about the 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 economic
OMA：D
这道题我做对肯定没有问题。但是，今天从新看的时候，发现一个问题，than后面的do对应的是哪个词？would？ have to？还是know呢？请教高人！！！作者: saiko13 时间: 2009-12-4 20:31
不知道我想的是不是对的，more than这种比较结构，无论前面的动词时什么时态than后面的动词总是用do来代表。我觉得这里的do 指代的应该是would have to know不知道我想的对不对？作者: xfyyds 时间: 2009-12-4 20:38
我觉得 指代 know more than now they know 把know 变成do了作者: cynthia627 时间: 2009-12-4 20:52
不知道我想的是不是对的，more than这种比较结构，无论前面的动词时什么时态than后面的动词总是用do来代表。我觉得这里的do 指代的应该是would have to know不知道我想的对不对？