The word "warned" is correct and usable in written English.
You can use it when you want to describe something in the past tense to indicate that someone was informed that something undesirable might occur if they did not take action. Example sentence: She was warned that she would be fired if she did not arrive to work on time.
Migrants who have permission to be in the UK are avoiding seeking vital medical treatment for fear of being arrested, a charity has warned.
The ambulance staff have warned the protesters that their legs have got very cold which makes the blood supply pool in their feet, this could lead them to faint and fall off the ledge.
Alexander made clear the Liberal Democrats' deep unease at the prime minister's plan when he warned of the dangers posed by those who "put anti-European ideology ahead of our national interest".
However, he warned that the service's achievements were now at risk.
Last June, the IPCC Fifth Assessment report warned of larger "near-term increases in seasonal mean and annual mean temperatures" in the region.
Writing days before Abdullah's death, the American author Stephen Kinzer warned that the basis of the west's relationship with the Saudi regime was shifting in fundamental ways, while Saudi Arabia's position in a region beset by insurrection and civil war was ever less secure.
Just as the Skibbereen Eagle grandly warned Kaiser Wilhelm in 1914 that it had its eye on him, so film reviewers feel moved to bellow their disapproval at the Academy.
Writing before the announcement that Australia was withdrawing its ambassador, he predicted the executions would affect Australians' perceptions of Widodo for the rest of his tenure, but warned against such a step.
He warned a decision to withdraw the ambassador could harm Australia's longer term goals.
Another witness was a British man who was supposed to join Richard Reid in a shoe-bomb attack in December 2001 but who quit the conspiracy during a trip home after his parents warned him that he better not be a terrorist.
