Conditional sentences. Wrong verb in the unreal “if” clause
As a refresher, the verb tense of an entire conditional sentence depends on the realness of the “if” clause. This is even more important with unreal or imaginative conditions because the relationships between its forms and meanings are unusual.
For instance, remember that the usage of the simple past tense in the “if” clause refers to a present or future event, but to indicate a conditional event happened in the past the “if” clause uses the past perfect.
Therefore, you not only have to indicate the realness of a conditional event but you must also determine if the real or unreal event happened in the past, is happening in the present or will happen in the future. The usage of an incorrect tense in the “if” clause is running the risk of misinforming the reader on the realness of an event and when it took place.