Identify the part of sentence that contains a mistake in grammar, idiom or syntax :
She was as pretty as, if not prettier than, any other girl who had come to participate in the meeting.Notice that we have added the word "as" after "pretty" and we have addedcommasbefore and after "if not prettier than." Now, the two comparative structures are grammatically parallel to each other. That is, "as pretty as" is now parallel, both grammatically and logically, to "prettier than."