nà / duàn / guó / nàn / shí / qī / de / lì / shǐ / , / wǒ / men / yǒng / yuǎn / bù / néng / wàng / jì / 。那段国难时期的历史,我们永远不能忘记。We must never forget the history of that period of national calamity.