国难的英文：
national calamity

Here is not merely a nation but a teeming nation of nations
这里不仅是一个国家，而是许多国家丰富的总和。

release of nationality
国籍解除; 放弃（脱离）国籍

a tributary nation
进贡国,2. 辅助的,3. 支流的,n.[C]1. 进贡国,附庸国[( to)]2. 进贡者,3. 支流

The conception of the United Nations was in 1945.
联合国创始于一九四五年。

She is a nationally known writer.
她是全国知名作家。

An optimist sees an opportunity in every calamity; a pessimist sees a calamity in every opportunity
乐观的人在灾难中看到希望;悲观的人在希望中看到灾难

An optimist sees an opportunity in every calamity.
乐观者在灾难中可以看到希望。

They will only triumph by persevering in their struggle against natural calamities.
他们只有坚持向自然灾害作斗争，才能取得胜利。

Calamity is man's true touch stone.
灾难是吾人真正的试金石。

For me, the July twentieth affair was in every way a calamity.
就我来说，七月二十日事件完全是大祸临头。