他们的友谊是由于共患难而结成的。用英语怎么说？

他们的友谊是由于共患难而结成的。

Their friendship was forged by sharing adversity.

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

friendship

n. 友情，友谊，友善的关系，友善，好意；

例句
Nothing cements a friendship between countries so much as trade.
贸易最能增强国家间的友谊。

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

forged

v. 锻造( forge的过去式和过去分词 )，伪造，艰苦干成，努力加强；

例句
His independence had been forged on the anvil of a harsh environment.
他的独立性是在艰苦的环境中锤炼出来的。

by

prep. 在…旁边，表示方式，由于，经过；adv. 经过，表示保留或保存时用，短暂拜访；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

sharing

n. 分配，均分，共价，共享；

例句
Three prisoners were sharing one small cell 3 metres by 2 metres.
3个囚犯关在一个3米长2米宽的小牢房里。

adversity

n. 逆境，不幸，灾难；

例句
I always turn adversity and defeat into victories, but it's probably put ten years on me.
我总是能够扭转逆境，反败为胜，但这可能让我显得老成了10岁。