Read the extract below and answer the question:
WILLIAM SHAKESPEARE: Twelfth Night

A : What country, friends, is this?
B : This is lllyria, Lady,
A : And what should I do in lllyria?
My brother he is in Elysium.
Perchance he is not drowned - What think you, sailors?
B : It is perchance that you yourself where saved
A : O my poor brother. and so perchance may he be
(Act 1 Scene II)

The figure of speech underlined in the extract is known as