Conditional sentences. “Was” instead of “were” in the unreal “if” clause
As a refresher, an unreal conditional sentence expresses events that are hypothetical or contrary-to-fact. Some “if” clauses use “were” even if the pronoun is singular. In these statements, the writer is specifying an event is impossible in the present or did not happen in the past. In addition, unreal conditional “if” clauses refer to event in the present, as in “If I were you, I would not do this.” In truth, the speaker is telling their audience “I am not you.”
This can present some problems for beginning writers or non-native English speakers. “To Be” is the only English verb with two past tense forms, but only “were” is used in unreal conditional sentences. Consider the following sentences:
If he were here right now, he would help us.
In this sentence, the speaker is really saying “He is not here right now.”