[求助]请教大全46

以下是引用dreadpower在2003-12-3 21:06:00的发言：
46.According to Interstudy, a nonprofit organization that studies health maintenance organizations (HMO’s), they estimate that, in comparison to last year, when only 36 percent of the nation’s 607 HMO’s was profitable, this year 73 percent will be.
(A) they estimate that, in comparison to last year, when only 36 percent of the nation’s 607 HMO’s was profitable, this year 73 percent will be
(C) only 36 percent of the nation’s 607 HMO’s were profitable last year; it estimates that this year 73 percent will be
(D) it estimates 73 percent of the nation’s 607 HMO’s would be profitable this year; last year that was only 36 percent
(E) only 36 percent of the nation’s 607 HMO’s last year were profitable, whereas they estimate it this year to be 73 percent
                 答案是C。
                 请教几个问题：
1。A选项中，in comparison to last year是否修饰73 percent ？？

in comparision to好像不对，至少应当是in comparison of . 比较对象到是相同．
2。D选项中，that was only 36 percent中的that肯定有问题，其逻辑指代对象和语法上指代对象肯定不同，那么它语法上应该指代什么？？？

that好像没有指代对象
3。E选项中，they estimate it this year to be 73 percent中的it也肯定错，想问它在语法上指代什么？？？