Soldiers have to learn discipline.

军人必须学会遵守纪律。

《新英汉大辞典》

Soldiers shave to learn discipline.

军人必须学会遵守纪律。

youdao

A few are sent by their parents to learn discipline and hard work.

还有一些人是被父母送到这里接受管教和学习吃苦精神的。

youdao

Parents argue that the sport is still a good way to learn discipline, self-confidence and self-reliance.

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But we are happy, we learn discipline.

BBC: News | NEWSNIGHT | Military academies transcript

The British Medical Association (BMA) said sports such as boxing and cage-fighting were "sometimes defended on the grounds that children learn to work through their aggression with discipline and control".

BBC: Boys' fight in cage 'very barbaric' says Jeremy Hunt