Died "of" is more correct but you would certainly hear both of them so often that neither would be considered incorrect by the listener. Use of either of them would be just fine.I'm sorry to hear that Mr. Lee died of/from heart failure.
Could I use both died of and died from here? Thanks.
In what context? Do you mean that it's reasonable to give them a "trick question" or that you want them all to get it right (which they will if both words are considered correct)?Thanks, Dimcl.
Since either one will work, is it reasonable to test students here with this kind of question?