according to the rules,children under 12 ____ be accompanied by adults if they wan to swim int the
问题描述：
according to the rules,children under 12 ____ be accompanied by adults if they wan to swim int the
pool.A.must B.might C.could D.shall 为什么选must?shall 不是可以用于规定条文中吗?
答
A
表示必须的