Last year, land values in most parts of the pinelands rose almost so fast,and in some parts even faster than what they did outside the pinelands.

A so fast,and in some parts even faster than what they did

B so fast, and in some parts even faster than, those

C as fast, and in some parts even faster than, those

D as fast as, and in some parts even faster than, those

Eas fast as, and in some parts even faster than what they did

这道题的答案是D，我有一个问题想请教：为什么those 所在的比较从局不加助动词did呢。在语法书比较一章中论述为：比较从句的主语和谓语与主局的主语和谓语相同时，可以全部省去，常保留作状语的介词短语或状语从句，这里没省those, 却没加did 是什么道理呢，我做过很多比较的语法题，有的补出助动词，有的没补。这里有什么规律呢。

一个困扰好长时间的问题，希望多多指教。

比较状语从句中的省略 在以than或as引导的比较状语从句中，如果主语与主句的主语一致，则从句主语与谓语（可以是be动词，也可以是行为动词）均可省略；如果从句的主语和主句的主语不一致，则省略其谓语及与主句相同的部分。如： Production is going up much faster than (it was) before. 生产比以前增加得快多了。 Jane can speak Spanish more fluently than Peter (can speak). 珍妮讲西班牙语比彼得讲得流利。 Winter in Guangzhou is not so cold as in Beijing. 广州的冬天不像北京的冬天那么冷。