Parallel structure also called parallelism btw is the repetition of a chosen grammatical form within a sentence.By Making each compared item or idea in your sentence follow the same grammatical pattern, you create a parallel construction. Not Parallel:Ellen likes hiking, the rodeo, and to take afternoon naps.Parallel:Ellen likes hiking, attending the rodeo, and taking afternoon naps.
a summary is for the audience to quickly grasp the entire article/story/passage(etc.), it should be short and sweet, consisting only of the key points. your personal opinions are not required. background information is unessential, because it would cause your summary to be too long, and summaries are meant to be short so as to bring out the main topics only, not cover the entire passage. minor examples are optional to include, but not needed as well.