问几道比较的语法题

露比Alice

1.189.Today’s technologyallows manufacturers to make small cars more fuel-efficient now than at anytime in their production history.

A.    small cars more fuel-efficient now than at any time in their

B.    small cars that are more fuel-efficient than they were at any time intheir
C.    small cars that are more fuel-efficient than those at any other time in
D.     more fuel-efficientsmall cars than those at any other time in their   (C)
E.    more fuel-efficient small cars now than at any time in

197. Soaring television costsaccounted for more than half the spending in the presidential campaign of 1992,a greater proportion than it was in any previous election.

A.    a greater proportion than it was
B.    a greater proportion than
C.    a greater proportion than they have been
D.     which is greater thanwas so       (B)
E.     which is greater than ithas been
第一道题：因为是现在生产的小汽车和过去生产的小汽车（两批不同的汽车）进行比较，所以不能用they指代前面的small carsy that。。。而是用those指代small cars
第二道题：it指代前面的 a greater proportion（1992年的）所以不可以。08笔记中说用that代替proportion表示比较 但是that省略了所以选b
我的疑问是 既然第二道题中的that 可以省略那么是不是第一道题中的those也可以省略？

露比Alice

懂得同学说一下见解 谢谢