If current trends continue, by the year 2010 carbon emissions in the United States will soar to a level more than one-third higher than were those in 1990, according to official projections. A.will soar to a level more than one-third higher than were those B.will soar to a level more than one-third higher than that C.would soar to a level more than one-third higher than it was D.would soar to a level more than one-third higher than those E.would soar to a level more than one-third higher than they were
答案是B,CDE直接通过if X happens, Y will happen排除掉,剩下A和B,我想问A中的were是多余还是应该改成did?B选项中的that用单数指代emissions是不是指代单复数问题呢?请NN指教,谢谢:)