What, when. What and when are often used as exclamations of impatience:
“When, Lucius, when?” Ib. 5. Some ellipsis is to be supplied, "What (is the matter)?" "When (are you coming)?" So in“What, Lucius, ho!
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See also What, 253.“Gaunt. Throw down, my son, the duke of Norfolk's gage.
K. Rich. And, Norfolk, throw down his.
Gaunt. When, Harry, when?
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