大全11-6

[吳]

6.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
D
句子的動詞是:could have
D是do代替 do (have)
映象中好像沒有不同的助動詞這樣用的,could have跟 do have應該不一樣吧...有嗎?
(雖然也沒其他答案好選囉...)
tks...