Abstract: Whether obligations can be produced by first act ,the key is to see if there is a duty.Any person must abide by the norms set by the laws. Once a person violates crimal norms, he or she should bear the criminal liability and has not the obligation to prevent harmful consequnces .Consequential in aggravated crime is the subjective will’s product, and legal omission is the product under the subjective will.Whether an act is an omission or an aggravated crime is decided by the fact that the subjective corresponds the subjective of an aggravated crime or not.