20. An array of tax incentives has led to a boom in the construction of new office buildings; so abundant has capital been for commercial real estate that investors regularly scour the country for areas in which to build.

A. so abundant has capital been for commercial real estate that

B. capital has been so abundant for commercial real estate, so that

C. the abundance of capital for commercial real estate has been such,

D. such has the abundance of capital been for commercial real estate that

E. such has been an abundance of capital for commercial real estate,

1.       惯用语（一级排除B,C,D,E）so/such  … that 结构

such … that  such 表示这种，无强调；而 so .. that 有强调的含义

A. so + adj. , so that 不合理

B.倒装：

根据主语和谓语相对位置，当句子的全部谓语都位于主语之前称之为完全倒装，当句子的部分谓语位于主语之前称为局部倒装句。举例：
1.Here comes the bus!(完全倒装句）

2.Only in this way can a good result be achieved.(局部倒装句)
本题A选项为局部倒装句，当构成结果状语从句so---that的so位于句首表示强调。

【so..that 】 (正常)capital has been so abundant that investors scour the country for areas .. 倒裝：so abundant has capital been that investors scour the country for areas ..→是部份倒裝型式
【such..that 】正常：an abundance of capital has been such that investors scour the country for areas.. 倒裝：such has been an abundance of capital that investors scour the country for areas..←完全倒裝型式 

C.Such/ so that 比较：

1.首先一点要明确, such 是形容词, 修饰名词或名词性的结构(such a good job, such good work, such a good person,...), 而so 是副词, 修饰形容词 ( a so good job, so good work, a so good person...)1. "such functions to mean "of a kind" rather than to intensify abundant." - 这样说是很有根据的. 因为such加强的是后面的名词, 重点是事物上. 而so加的强是后面的形容词. 这里的需要语感去体会.

2. 我个人在改错题中的一个发现是, 如果选项中有到装句, 要特别留意. "so abundant has capital been for commercial real estate that", 就是. 到装句成为正确答案的可能性非常大. , (大家去验证一下, 有例外的请发贴). 原因可能是因为到装句是英语中一种固定的结构, 它可以突出,强调重点, 使表达更清晰, 和GMAT对句子的要求一致. 而到装句结构和一般的句子不一样, 容易被人看成是错句!

2. 单复数：A of B + 谓语，谓语的数和 A一致。An array of tax incentives has led to