One unbreakable rule in our school is that no child can be tested without written parental permission.我们学校有一条金科玉律：未经父母书面同意，不得对学生进行测试。Wearing uniform is an unbreakable rule in our school.穿校服是我们学校的一条金科玉律。I try to live by the Golden Rule.我努力奉行己所不欲，勿施于人的金科玉律。