This was not the time to take risks; he knew he should play it by the rule book.
这不是冒险的时候,他知道他应该按规则行事。
《柯林斯英汉双解大词典》
2
She makes it a rule to enjoy pop songs in her spare time.
她习惯在空闲时间听一些流行音乐。
3
Given the amount of time we spend in classrooms, and the number of shoes that pass through them every day, you may well understand me if I were to propose a no-shoes-in-the-classroom rule.