1. Act 1, Scene 2: She is present at the court, where she is informed of Hamlet's mourning and the news of her late husband's death.
2. Act 3, Scene 1: She is present during the "Mousetrap" play, where she is deeply affected by the performance's content, especially the scene depicting a queen poisoned by her own husband.
3. Act 3, Scene 3: She is present in her private chamber when Hamlet confronts her about her hasty marriage to Claudius.
4. Act 4, Scene 7: She is present in the king's chamber when she drinks from the poisoned goblet, leading to her tragic demise.