crucible

这场战争是对人性的严峻考验。

The war became a ___crucible that tested human nature.

工匠将金块放入坩埚中熔化。

The artisan placed the gold nugget into the ___crucible to melt it.

初创公司残酷的第一年成了一种熔炉般的考验，锻造出了一支坚强团结的团队。

The startup's brutal first year served as a ___crucible that forged a strong, united team.