It was the fog that caused the traffic problem. → If it __________________________________________________________________________

It was the fog that caused the traffic problem.

→ If it hasn't been for the fog, it wouldn't have caused the traffic problem.

Câu điều kiện loại 3 để diễn tả sự việc đã xảy ra

CT: IF + S + HAVE/HAS + PP, S + WOULD + HAVE + PP.