198. Although Napoleon’s army entered Russia with far more supplies than they had in their previous campaigns, it had provisions for only twenty-four days.
(A) they had in their previous campaigns
(B) their previous campaigns had had
(C) they had for any previous campaign
(D) in their previous campaigns (E)
(E) for any previous campaign
AC的谓语动词had补错, 应该是had had.
92. Never before had taxpayers confronted so many changes at once as they had in the Tax Reform Act of 1986.
(A) so many changes at once as they had in
(B) at once as many changes as
(C) at once as many changes that there were with
(D) as many changes at once as they confronted in(D)
(E) so many changes at once that confronted them in
同样一群taxpayers前后发生的事情比较，却在than后补出了主语及谓语. D的confronted补的完全正确, A中的had就是错的。另外，D中代词用了they, 而不是that/those， 因为是自己与自己比。that/those指代同类事物，而不是同一样事物。
X had had....than X had... 后面一个had是过去完成时，而非过去时。
X had...than X had... 后面一个had是过去时, 而非过去完成时。
Innits of the Bering Sea were in isolation from contact with Europeans longer than Aleuts or Inuits of the North Pacific and northern Alaska.
(A) in isolation from contact with Eurpoeans longer than
(B) isolated from contact with Eurpoeans longer than
(C)in isolation from contact with Eurpoeans longer than were
(D) isolated from contact with Eurpoeans longer than were (D)
(E) in isolation and without contact with Eurpoeans longer than
isolated from contact with Eurpoeans longer than from。。。补出from
isolated from contact with Eurpoeans longer than were。。。补出were
两种补出方式(prep. or 动词)产生的意思完全不一样，所以要补出were消除歧义。
结论：不同主语之间的比较可以省略谓语动词，但前提是没有歧义。我看到网上有些说法，认为实意动词不能省略，但系表结构就可以。这种说法很片面，所以我特地举了一个系表结构而不省略的例子。引用一位前辈的话：“。。。ETS如此的reluctant to purport 什么硬性的公理。如何将一个句子表达得准确，简洁，不产生歧义是ETS对句子改错的最高要求。有一些通常的做法，但是决不能生搬硬套。”
The question of whether to divest themselves of stock in companies that do business in South Africa is particularly troublesome for the nation's 116 private Black colleges because their economic bases are often more fragile than most predominantly White colleges.
(B) than those of
(C) than is so of
(D) compared to (B)
(E) compared to those of