tā / dāng / zhòng / lì / xià / jūn / lìng / zhuàng / bǎo / zhèng / yuè / dǐ / qián / wán / chéng / rèn / wù

他当众立下军令状，保证月底前完成任务。

He publicly made a solemn pledge to finish the task by the end of the month.