I meet an excellent idea and really want to use it. The author allows me to do that, but I can't just copy the whole text. The problem is, I do want to use my own language, but in each sentence they have organized keywords in perfect combination, making it much concrete and enlightening, and I really don't know how to put it in another way. It's like a perfect quote or essay from a book that you just can't add or remove any word (or such modification can't be substantial). What should I do?