You can also assure him that when they happen, they are investigated carefully, to identify causes and help prevent it from happening again. (childmind.org)
What we've found is that the graphene layer prevents this from happening by stopping contaminants in the air from attacking the silver. (sciencedaily.com)
If you can't identify when something bad is about to happen, you can't prevent it from happening. (dogtrainingnation.com)