3 sentences

1. 在国家危难之际，他挺身而出。

   zài guó​jiā wēi​nàn zhī​jì, tā tǐng​shēn'ér​chū.

   He stepped forward in the nation's time of peril.

   Source: Dong Chinese Dictionary

2. 他在危难时刻受命出任临时主席。

   tā zài wēi​nàn shí​kè shòu​mìng chū​rèn lín​shí zhǔ​xí.

   He was appointed as interim chairman in a time of crisis.

   Source: Dong Chinese Dictionary

3. 他在危难时刻表现出了对国家的高度忠心。

   tā zài wēi​nàn shí​kè biǎo​xiàn chū le duì guó​jiā de gāo​dù zhōng​xīn.

   He showed great loyalty to the country in times of peril.

   Source: Dong Chinese Dictionary