2. Since 1981, when the farm depression began, the number of acres overseen by professional farm-management companies have grown from 48 million to nearly 59 million, an area that is about Colorado's size.

A. have grown from 48 million to nearly 59 million, an area that is about Colorado's size
B. have grown from 48 million to nearly 59 million, about the size of Colorado
C. has grown from 48 million to nearly 59 million, an area about the size of Colorado
D. has grown from 48 million up to nearly 59 million, an area about the size of Colorado's
E. has grown from 48 million up to nearly 59 million, about Colorado's size

1. 主谓一致:the number of + 复数名词做主语，后面的动词用单数。Since + 时间，是现在完成时的标志。

2. 简洁：定语从句的省略
a.that做定从中主语，不可省。there is a girl that(who) has green hair..
b that做定从中宾语，可省，也可不省。there is a book (that) you have not read.
c 有that be/which be引导的定从，能省就省。there is a book (that was) borrowed by mary yesterday.
名词＋that＋be+分词/介词等一般没有分词＋名词或者名词＋介词等的形式简洁；不过还是需要逻辑判断的，如果是名词＋that +情态动词＋be＋分词/介词大多数不要使用上面大额原则，否则意思改变；
* 定语从句的that: 省略 & 宾语从句的that: 不省

3.逻辑意思清晰（此题about前边要有名词）
同位语结构
同位语是GMAT的优先结构；当补出概括性名词的时候更加清楚。介词短语前面一定要有所修饰的名词

4．习语： 
from x to y ; 改成 from x up to y 错！

5. 所有格错：
a..双重所有格必错，The A of B’s。
b. A 's主要用于表示有生命的东西，另外表示时间（today 's papers)、人组成的集体(government 's policy)、国家城市（Beijing 's parks）、某些机构（hotel 's entrance) 的名词也可用
c. A of B , B 通常为物.但是这一点在 GMAT中不要作为第一位
朗文英语语法（名词-所有格）：一般不使 'S与无生命的东西连用。但与地理、机构有关的，可以用 'S / S' 或 of 结构，例如 Amercia's policy, the European Economic Community's exports
下列情况一般用 'S / S'：地名+最高级，教会和教堂，和时间有关的，“值多少钱”，固定说法。例如 New York's tallest skyscraper, St Paul's Church, a day's work, an hour's delay, a month's salary, two days' journey, twenty dollars' worth of gasoline, 固定说法at arm's length, the earth's surface
关于's 这个问题，ETS考的非常灵活, 很多没有生命的都加了, 建议不要把除了双重所有格以外的和's相关的东西作为排除点.

6. Nearly
nearl否定形式通常用hardly / scarcely / barely 来代替。例如：
I almost / nearly didn't get up in time.
I hardly / scarcely / barely got up in time.