# Why were you searching for me?
Jesus uses two questions to mildly rebuke his parents. Alternate translation: "You did not need to look for me."
# Did you not know ... business?
This question can be translated as a statement. Alternate translation: "You should have known ... business."
# I had to be about my Father's business
Possible meanings are "I had to do the work my Father gave me" or "I had to be in my Father's house." When Jesus said "my Father" he was referring to God, but his parents may not have understood that.