一、省略結(jié)構(gòu)分析

　　The guiding principles of the tax plan released by the Treasury Department could have even a greater significance for the economy than the particulars of the plan.

　　(A) even a greater significance for the economy than

　　(B) a significance that is even greater for the economy than

　　(C) even greater significance for the economy than have

　　(D) even greater significance for the economy than do

　　(E) a significance even greater for the economy than have

　　考察比較中的省略結(jié)構(gòu)。

　　也就是than后面到底是沒(méi)有助動(dòng)詞，還是加do,或者是have。首先than后面如果有助動(dòng)詞的話，必然是事情和事情的比較，也就是句子間的比較，GMAT語(yǔ)法如果沒(méi)有助動(dòng)詞就是than前后名詞的比較。GMAT考試Do 和have的取舍在于前面的時(shí)態(tài)，如果前面是一般時(shí)態(tài)就用do的形式，如果前面是完成時(shí)就用have的形式。

　　這里很顯然是事情和事情的比較(principles 和particulars各自have significance的比較)所以需要助動(dòng)詞，因?yàn)榍懊媸且话銜r(shí)態(tài)，GMAT入門生都知道所以用do,選擇D

　　另外，significance是不可數(shù)名詞。

　　二、after的妙用

　　1 after doing 相關(guān)問(wèn)題

　　220. (GWD-24-8, OG12-86)The results of the company's cost-cuttingmeasures are evident in its profits, which increased five percent during thefirst three months of this year after it fell over the last two years.

　　A. whichincreased five percent during the first three months of this year after it fell

　　B. whichhad increased five percent during the first three months of this year after ithad fallen

　　C. whichhave increased five percent during the first three months of this year afterfalling

　　D. with a five percent increase during the firstthree months of this year after falling (C)

　　E. with a five percent increase during the firstthree months of this year after having fallen

　　答案選C，但解釋上有點(diǎn)問(wèn)題我不明白：下面是語(yǔ)GMAT語(yǔ)法筆記上對(duì)于B和C的解釋：

　　B. after it had fallen時(shí)態(tài)上沒(méi)有問(wèn)題，可以與over the last two years搭配，但是不如after falling簡(jiǎn)潔

　　C. Correct;afterfalling簡(jiǎn)潔，狀語(yǔ)從句的省略

　　求助GMAT考試討論：可是我不理解為什把a(bǔ)fter doing理解為狀語(yǔ)從句的省略。我覺(jué)得這里不是省略!!!

　　狀語(yǔ)從句的省略：從句主語(yǔ)和主句主語(yǔ)一致，并且包含be。。。從句主語(yǔ)和be可以省略。when，although ，等詞引導(dǎo)時(shí)間狀語(yǔ)從句，讓步狀語(yǔ)從句等時(shí)，可以用這種形式來(lái)簡(jiǎn)潔表達(dá)。

　　但是如果把這里的after doing 理解為 after it have/had been falling。我覺(jué)得也不能清晰的表達(dá)出原文所想表達(dá)的時(shí)態(tài)先后關(guān)系。而且如果這里 fall是進(jìn)行時(shí)表達(dá)一直在下降，這里也是不對(duì)的吧。