In that case, you probably read the questions first and then read the passage in order to find the correct answer. Pay attention to the author's arguments as well as the tone of the text. Words that are repeated several times are likely to be keywords. Be careful to use your own words rather than copying or just rearranging.
However, if you want to comment on a piece of writing it is usual to begin by summarizing it as objectively as possible. For example, you could look for all the topic sentences.
Transition words and phrases should help you to understand how the piece is joined together. A good summary may use key words from the original text but should not contain whole phrases or sentences from the original unless quotation marks are used.
Write down the author's thesis statement, the heading and subheading titles, and author's conclusion. References Serwer, A. For example, if the piece of writing is about digital technology, it is fine to use key technical words that are in the original, such as "digital technology", "binary digit" or "analog".
Give a full reference for this citation at the end of the summary see 6.