问个than的问题，NN请进

cdpku2002

正确例子，
New techniques in thermal-scanning photography, a process that recordsradiation from surface areas, have made it possible to study in greaterdetail than ever before the effects of calefaction, or warming, of a river.

With a total population of less than two hundred and fewerbreeding females than ever before, the American crocodile seemed a decade agoto be in danger of disappearing

显然than ever before是可以接受的.

但是从下边的例子可以看出than now, than five years ago是不行的，那位NN可以解释一下？

正确的
A large rise in the number of housing starts in the coming year should boost new construction dollars by several billion dollars, making the construction industry’s economic health much more robust than it was five years ago.

错误的
A large rise in the number of housing starts in the coming year should boost new construction dollars by several billion dollars, making the construction industry’s economic health much more robust than five years ago.


正确的
To develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the social and economic.

错误的
To develop more accurate population forecasts, demographers would have to know a great deal more than now about the social and economic.

cdpku2002

Up

typhoon_wang

我觉得是比较对象的问题

但是具体不知道怎么说  

帮你UP一下....

aeoluseros

时态变了，是要补出主语和动词的

coolwave888

斑竹大人~~可是上面给出的正确句子than ever before,明显是过去时跟前面的时态也不一致啊，如果那样，也要补出主语动词的。我觉得是不是比较的对象的问题。下面比较经济健康和知识多少的比较成分是宾语或者宾语补足。而than ever before 的例子比较的是介词of ,in后面的内容。不知真正的语法规则是什么，还望
open to disscussion.....

eshopaholic

感觉还是比较对象的问题

若是主语/谓语（或是修饰谓语的成分），可省

若是宾语/表语，则需补出


个人 看法，大家批