人参与)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
考察比较中的省略结构。
也就是than后面到底是没有助动词，还是加do,或者是have。首先than后面如果有助动词的话，必然是事情和事情的比较，也就是句子间的比较，如果没有助动词就是than前后名词的比较。Do 和have的取舍在于前面的时态，如果前面是一般时态就用do的形式，如果前面是完成时就用have的形式。
这里很显然是事情和事情的比较（principles 和particulars各自have significance的比较）所以需要助动词，因为前面是一般时态，所以用do,选择D
另外，significance是不可数名词。
