He was later let off with a stern warning from the police.
Didn't let him do it without a stern warning.
Later, his mother said, she gave him a stern warning after he kicked a helmet.
But before giving her the money, he added a stern warning.
Several times, a stern warning prevented one or two from running down to join the visitors.
I remembered my father's stern warning not to discuss the incident with anyone.
But he gave a stern warning: "You've got to take this issue out of the political box."
He gave a stern warning against the dangers of the arms race.
The court gave a stern warning against future attempts to scoop it.
Included was the stern warning to include coffee breaks, or the report would be considered false.