[Nurse:] Marry, and amen, how sound is she asleep!

I needs must wake her. Madam, madam, madam!

Ay, let the county take you in your bed;

He'll fright you up, i' faith. Will it not be?

What, dress'd! and in your clothes! and down again!

I must needs wake you. Lady! lady! lady!

Alas! alas! Help! help! my lady's dead!

O! well-a-day, that ever I was born.

Some aqua-vitae, ho! My lord! my lady!

–Romeo and Juliet,
William Shakespeare

Why is this a moment of dramatic irony?

The audience knows that Juliet plans to marry Paris, but the nurse does not.
The audience knows that Friar Laurence will betray Juliet, but Juliet does not.
The audience knows that Juliet is not really dead, but the nurse does not.
The audience knows that Lady Capulet has figured out Juliet’s plan, but Juliet does not.

The answer is: The audience knows that Juliet is not really dead, but the nurse does not.