If something is obligatory, you must do it because of a rule or a law. 规定性的
adjective [原级] 有义务的，强制性的；惯常的，赶时髦的；（规定，裁决）有约束力的
Most women will be offered an ultrasound scan during pregnancy, although it's not obligatory. 大部分妇女怀孕期间都将进行超声波检查，尽管不是规定性的。
- 网友用 “Obligatory” 造句精选
- It is obligatory for all employees to wear protective clothing. 所有员工必须穿防护服装。
- Priority must be given to the development of obligatory activities. 必须优先发展义务活动。
- In the mid 60s he took the almost obligatory trip to India. 六十年代中期，他也赶时髦到印度一游。