执法部门的主要职责是公正地执行法律。

The primary responsibility of law enforcement is to ___enforce the law impartially.

学校当局必须严格执行关于在教室使用手机的规定。

School authorities must strictly ___enforce the rules regarding mobile phone usage in classrooms.

对于监管机构来说，有效执行新的环境法规是一项挑战。

It is challenging for the regulatory body to effectively ___enforce the new environmental regulations.