Past Possibilities
Sample 1.
WRONG : If you were not late for the press conference, you would have heard the Director’s speech.
CORRECT : If you had not been late for the press conference, you would have heard the Director’s speech.
Sample 2.
WRONG : If the project was not delayed, we would have finished it by now.
CORRECT :If the project had not been delayed, we would have finished it by now.
When referring to something which could have happened but did not, we use past perfect in the if clause and would have + past participle in the main clause.
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