The past subjunctive "if clause" structure -- mournful, a study in sepia, the fate of the main clause held hostage by an impossible conditional, its hope tethered to a sinking stone. "If I were a rich man…" runs one famous example, "All day long I'd biddy biddy bum." (And who wouldn't?) The problem is, "you use the subjunctive," The American Heritage Book of English Usage says, "to describe an occurrence that you have presupposed to be contrary to fact." The statement "If I were a rich man" tells us that the speaker is, lamentably, not rich.