学生要遵守学校纪律。

Xuéshēng yào zūnshǒu xuéxiào jìlǜ.

Students must follow school rules.

老师有责任维持课堂纪律。

Lǎoshī yǒu zérèn wéichí kètáng jìlǜ.

Teachers have a responsibility to maintain classroom discipline.

军队要严守纪律。

Jūnduì yào yánshǒu jìlǜ.

The army must strictly observe discipline.