of和as均为介词，放在一起导致了语法错误。
opponent：对手，敌对的
看到这种极简题目的时候，尤其是单复数谓语都出现，要考虑从句到底在修饰哪个词语

Yes, we can use "think of X as (noun)," but I can't think of a case where "think of X as (adjective)" is useful. It would be easier just to say "think X is (adjective."

The noun form is used when we want someone to look at something a different way:

Person 1: "Thanks for paying for dinner, but you didn't have to do that."
Person 2: "Think of it as an early birthday present."

嵌入式关系分句：有一种关系分句(即定语从句)，它既是先行词的后置修饰语(即定语)，同时又是另外一个分句结构的宾语(即宾语从句)
In his breastpocket he had a patch of scarlet, which I suppose was the paper cap serving as a handkerchief.
还原进定语从句并补全省略部分，则有：
I suppose (that) patch of scarlet was the paper cap serving as a handkerchief.

注意理清语义，本题的宾语应是statements about an opponent 而不是opponent！
即：A recent poll of elected officials suggests that candidates, when in the midst of a tough campaign, often make statements about an opponent that they may not think are true.
最近一项对当选官员的民意调查显示，在激烈的竞选中，候选人往往会发表自己可能认为不真实的关于对手的言论。

think of something as something---correct
think of something as + adj. ---incorrect

think 约束力弱，后面应该加从句而不是to do
嵌入式关系分句
综上所述，当先行词在定语从句中充当的成分是另一个从句（宾语从句）的某个成分时（正常来说，先行词），则我们可以称这个定语从句为嵌入式关系分句，也就是将这个宾语从句嵌入到了定语从句中。

A ture的主语是statements而不是opponent
B 正确
D think of X as Y XY都是名词；think X is adj
E it没有指代
C think to be 不符合语言习惯

“按照嵌入式关系分句的概念，该句可以还原为：
they may not think (that) an opponent is true.”
定语从句修饰的先行词是它这句定语从句的宾语，这个时候可以省略这个宾语！！！

剩B、C，错选C。think的用法，约束力弱。

中心词是 statements ，about an opponent是介宾修饰！

m

A、is则根据就近修饰原则，定语从句that they may not think is true必然修饰一个最近的单数名词。按照嵌入式关系分句的概念，该句可以还原为：they may not think (that) an opponent is true在逻辑上，它们可能不认为对的，应该是“言论”，而不是“对手”，而is谓语动词单数，就近修饰单数名词opponent“对手”作主语，“对手错”语意错
B、are 谓语动词复数，就近修饰复数名词先行词statements作主语，“言论错”OK
C、从句可以跳跃修饰名词statements，代入先行词则有：they may not think statements to be true. 复合宾语，考查不定式和从句的区别。由于think是看法类动词且属于主动语态，所以约束力较弱，应该用宾语从句，而不能用不定式短语
D、of as，of和as均为介词，放在一起导致了语法错误
E、they may not think (that) it is true.该定语从句中什么成分也不缺少，导致了先行词无法在定语从句中充当任何成分

如果用to be，这句话是缺少动词的
they may not think the statement to be true是错误表达，一般来说think to be会被用成被动，be thought of to be

they may not think是插入语，可以省略不看
还原之后：make statements about an opponent that（）are true［that指代了statements］

opponent，对手，反对者；advocate，拥护者
反对者没有true or false，that修饰的是statements，statements are not true。

将A/B的is/are分别代入原文，看哪个的用法更优，而不是主观挑选一个选项。

不定式和定语从句的区别，与动词的约束力有关！

think to be 不是很地道的英语表达。这也是排除C 选项的原因。
至少think are是肯定没错的

填入的to be后，该定语从句不再是嵌入式关系分句，就算该从句可以跳跃修饰名词statements，代入先行词则有：
they may not think statements to be true.
复合宾语statements to be true需改为宾语从句。这点考查了不定式和从句的区别。由于think是看法类动词且属于主动语态，所以约束力较弱，应该用宾语从句。

often make statements (about an opponent) that they may not think (the statements) are true.

that cannot refer to opponent (ppl), only who could refer to opponent, thus in this place, that refers to statements

。按照嵌入式关系分句的概念，该句可以还原为：
they may not think (that) an opponent is true.
在逻辑上，它们可能不认为对的，应该是“言论”，而不是“对手”。
把about an opponent扔了 知道that代指前面的statements就好做了
关于【think to be】
This pattern is not usually used unless think is in the passive. 此句型通常仅限于 think 用作被动语态。