What is an "antecedent"?

The antecedent is the word the pronoun is referring back to. In the following sentences, what might be the antecedent of the pronouns? You wouldn't know for sure since you can't see the paragraph.

  1. Why is he looking at me?
  2. She gave them a big hug.
  3. The other day they skipped school and were severely punished!