In this key university only under special circumstances _______ to take make-up tests.A are students permitted B permitted are students c students are permitted D.are permitted students 为什么选B?

标准答案：
这道的答题根本是要看明白意思。“这个重点大学，仅有一些特别准许的情况，学生可以补考”
A、根据汉语意思，完全不对，不可能是允许的学生
C、也不可能情况学生，那就是汉式英语
只有B、D是排除后最佳选择，但是答案D、从语法分析完全不对，in this key university是状语，这句话主语是special circumstances，are permitted 是谓语动词，而后面students在D答案根据语法是无法解释的。只能选择B
B、In this key university only under special circumstances permitted are students to take make-up tests.
分析：in this key university 地点状语
only under special circumstances permitted 句子主语（permitted做前面circumstances的后置定语）
are 系动词
students to make-up tests 为句子的表语（后面的不定式to make-up tests是表语成分里students的后置定语）

如果加个标点符号，就是
In this key university， only under special circumstances （ are students permitted ）

不难看出这是only 位于句首的倒装

正常语序是,students are permitted only under special circumstances

因此，倒装以后，是A are students permitted

应该选Aonly under special circumstances 前置,主谓要倒装正常的顺序是:In this key university,students are permitted to take make-up tests only under special circumstances.