The end of Communism is a serious warning to all mankind.

In the meantime, take this as a most serious warning from one who loves you.

However, during June 2008 another, more serious warning emerged.

There was no basis in fact for giving them a more serious warning than what you did.

I saw that as a serious warning, and have never returned to the top.

Omar had a rather serious warning of his heart condition three months ago.

They didn't even realize it was a serious warning.

He said, under his breath, "We got a serious warning.

The growing number of people who do not vote should be a serious warning to us.

East Timor took that violence as a serious warning and stepped up its training.