A commentary is a detailed explanation from the author's side, the expression of his/her opinions about whatever is being discussed or referred to. In other words, we can say that a commentary is when an author provides an explanation about the events or a situation.
One of the primary reasons why writers use commentaries is to provide explanations and also their analysis of evidence that's been provided or given. This allows the writer a chance to express his/her opinions about that particular point or the point made or argued about in a text.
