The first point I would like to make is:Code:The problem would not have been resolved had it not been for our action to conduct more tests before and after further review and scrutiny.
I would use a passive voice, would not have been resolved.
The second point is about different types of the conditionals.
Therefore, we are dealing here with the third conditional.Code:'had it not been for' = 'if it had not been for'.
The meaning of the sentence is:
Code:As there was our action to conduct more tests before and after further review and scrutiny, the problem was resolved.
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