GWD 3-27 that指代的疑惑.

Competition in the mid-nineteenth century by large western farms gradually caused farmers in Pennsylvania to turn to livestock raising, but before that it was predominantly grain-producing.

1. Competition in the mid-nineteenth century by large western farms gradually caused farmers in Pennsylvania to turn to livestock raising, but before that it was predominantly grain-producing.
   
2. Once predominantly a grain-producing state, competition in the mid-nineteenth century from large western farms gradually was causing Pennsylvania’s farmers to turn to livestock raising.
   
3. Pennsylvania’s farmers were gradually caused to turn to livestock raising by competition from large western farms in the mid-nineteenth century, but before that it was predominantly a grain-producing state.
   
4. It was once predominantly grain-producing, but competition in the mid-nineteenth century by large western farms was gradually causing Pennsylvania’s farmers to turn to livestock raising.
   
5. Pennsylvania was once a predominantly grain-producing state, but competition in the mid-nineteenth century from large western farms gradually caused the state’s farmers to turn to livestock raising.

答案是E, 没有疑问, 但是有一个问题不解.

A中的it指代不明确是没有争论的, 但是that是指代什么? 感觉似乎是在指代前面的整个句子, 但是that可以这样指代吗? 是否存在错误?

请教了!

that 可以代指上文整句话的内容.

我的看法不同,that指代整个句子的用法,我在gmat语法里面没有见过

常用that的指代一般在比较句中的省略,除此,没有想到例子

请牛牛举例.

Competition in the mid-nineteenth
century by large western farms gradually caused farmers in Pennsylvania to turn
to livestock raising, but before that it was predominantly grain-producing. 

A.   
Competition
in the mid-nineteenth century by large western farms gradually caused farmers
in Pennsylvania to turn to livestock raising, but before that it was
predominantly grain-producing. ///that不能指代前面的动词,或者整句. 2. Competition by large farms 不对.

B.    Once predominantly a
grain-producing state, competition in the mid-nineteenth century from large
western farms gradually was causing Pennsylvania’s farmers to turn to livestock
raising./// 1.副词predominantly 修饰名词错误.2 过去进行时态不对. 3

C.   
Pennsylvania’s
farmers were gradually caused to turn to livestock raising by competition from
large western farms in the mid-nineteenth century, but before that it was predominantly
a grain-producing state. ///1.that指代问题 2. It不能指代所有格占有的词.

D.   
It
was once predominantly grain-producing, but competition in the mid-nineteenth
century by large western farms was gradually causing Pennsylvania’s farmers to turn to livestock raising./// it指代问题 2. By介词修饰competition不对;  3. 过去进行时不对

E.    
Pennsylvania was once a predominantly
grain-producing state, but competition in the mid-nineteenth century from large
western farms gradually caused the state’s farmers to turn to livestock
raising.  E

OG里面有明确的说明that指代前面的动词或者句子是错误的,