>if i put straight between bad comb the bees will fix the bad?
No. They will never fix the bad. They don't view it as bad. But if you put an empty between two straight BROOD combs, they will draw a straight comb between. If you replace the last comb with a straight comb, the odds of the next being straight improve. Be careful, especially if SHB are an issue where you live, having the face of a comb against the face of another comb as they small hive beetles will leverage that to get started.