1. The toughness of a material can determine its durability.
材料的坚韧性可以决定它的耐久性。
2. He showed great toughness during the difficult times.
在困难时期，他表现出了极大的坚韧性。
3. The toughness of the competition was unexpected.
竞争的残酷程度出乎意料。