Dramatic Irony

• As an audience, when the witches prophesise that Macbeth will become the Thane of Cawdor, we already know this to be true - the witches seem important as a result.
• When Macbeth is speaking with Macduff about Duncan, Macbeth and the audience are aware that Duncan is dead. This builds suspense as the audience were not party to the death itself so we will finally learn what happened and whether Macbeth will be discovered as the killer (2:3).