If you find yourself debating whether to use “was” or “were” in a sentence, it’s likely that you’re dealing with an unreal conditional sentence. As a refresher, an unreal conditional sentence expresses events that are hypothetical or improbable.
Typically, an unreal conditional sentence begins with an if clause containing the past tense or past perfect tense of a verb followed by a conditional clause containing a modal verb such as “would.” Consider the following sentences:
Remember, though, that this exception applies only to unreal conditionals—that is, situations that do not reflect reality. (Hint: unreal conditionals often contain words like “would” or “ought to.”) When you’re talking about a possibility that did happen or might be true, use “was” and “were” as you normally would.