One of our rules is that every student wear school uniform while at school.
A. might
B. could
C. shall
D. will
网友回答
A. might
B. could
(答案→)C. shall
D. will
解析：考查情态动词。句义：其中一项规定就是每个学生在学校必须穿校服。根据关键词rules知道这是按规定，shall的具体用法：一三人称的疑问句，表征求对方意见；二三人称的陈述句表允诺，威胁，命令，警告等，还有就是按规定（制度，法律，协议等），所以C正确。