"I didn't know the food was yours," or,
"I didn't look to see who the food belonged to."

"I can't do it," or,
"I will learn how to do this."

"No one told me," or,
"I didn't think to ask."

The language you use to admit your faults matters.
When you say, "I didn't know..." we are not acknowledging our inaction. Instead, saying, "I didn't look to see who the food belonged to," clearly shows our self-awareness and suggests what we can do to better ourselves in the future.

Don't limit yourself by using vague language.
Be specific.
Be accountable.