It was just her way of telling him she had discovered the reason for his anger.
But I haven't got time now to discover the reason.
It was then that we discovered the reason for our ordeal.
No, do not seek any longer to discover the reason.
But he soon discovers the real reason for his investigation.
But it was then he discovered the reason for her fever.
Scientists must be trying to discover the reason for the phenomenon.
"You might take that as another subject: Try to discover the reason for all this heat."
Win your bet, and you'll discover the reason for it.
But she had never been able to discover the reason why.