Hello Alan, Mister Micawber, Beeesneees, Mordant, Esl_Expert and other native English speakers,
grammar-quizzes.com/condition3c.html
If I had known (that) your dog [color=green]is / [color=red]was agressive, I wouldn’t have offered to feed it. (noun clause – existing truth – The dog was agressive then and still is now.)
The parenthetical explanation isn’t clear to me. Are [color=green]is and [color=red]was interchangeable in this sentence?