[求助]问一个关于比较省略的句子

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

根据BY所说 助动词或情态动词+verb的时候 省略为助动词或情态动词，这里是could have为什么省略后为do 不是could呢？

同问

顶一下