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。 | 
