1. The impact of their actions on the environment is inexpungible, and we must take immediate steps to address it.
他们的行为对环境的影响是不可撤销的，我们必须立即采取措施予以解决。

2. The memories we create with loved ones are inexpungible and can never be erased.
与亲人们创造的回忆是永久存在的，永远无法抹去。