One of the rules is that under no circumstances to bring food drink or chewing gum into t

问题补充：

One of the rules is that under no circumstances to bring food, drink or chewing gum into the school.

A. students are allowed

B. allow students

C. are students allowed

D. students be allowed

答案：

A. students are allowed

B. allow students

(答案→)C. are students allowed

D. students be allowed

解析：考查倒转句。当否定词或者半否定词放在句首的时候，后面的主句使用部分倒装的形式。本题表语从句中的under no circumstance意为：绝不.是一个否定词，故使用部分倒装的形式。故C正确。