But you can't at once, cried Tuppence.
Tuppence was in disbelief, not knowing how to respond to such a situation, stuttering to let out "You cannot at once!".
mnli hypothesis: Tuppence was in disbelief, not knowing how to respond to such a situation, stuttering to let out "You cannot at once!". premise: But you can't at once, cried Tuppence.