请教OG12--41 ！！

emmahsu

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    D
E.    would have to know a great deal more than now about the social and economic
看了好多讨论帖，但有个问题不明白~请教大家：
demographers have to konw a great deal more than... 中a great deal of与more都是什么成分？  
a great deal是n.么？是的话就是konw的宾语？ 还是more本身是作为know的宾语，表数量
好多人貌似认为a great deal是名词，那么more是修饰great deal的adj.,还是修饰know的adv.？
谢谢~！

trtwarrior

a great deal 是副词，修饰more，表程度。

你可以把a great deal more理解为是much more的等价。这样便于你理解。。。

不过，在下觉得，这种很细节的结构问题没必要深究

emmahsu

我是这样想的，如果more是konw的宾语的话，那么这个题比对象就是

knowlege，差异在于n.,因此than后不能只写than now,否则就变为比较状语也

就是know的时间了如果more是修饰know，这题就变为比较动词的know的程度，

所以than后省略they do个人觉得就米什么问题了，因为恰好是状语在比较。
根据OG的解释，说是A：than now 错把knowledge和now相比，据此看来，OG应

该是认为是第一种情况，也就是more/a great of是kown的宾语，在比较宾语

而非状语，所以要补they do
是不是理解有点偏~
因为总觉的GMAT里号多题纠结于than后能不能只剩状语~

appleontree

我想问一下economic和economical有什么区别啊？

emmahsu

economic：经济上的。跟经济有关~economical：节俭的。比如很抠门~
两个意思不一样的，字典一下就可以~

dongstar

我也在看这道题    纠结为什么这里they do 不能省略
我没有用lz那么严密的分析方法   不过我觉得a great deal是用来修饰more的