We know we have to read "between the lines" to get the most out of anything. Marking up is also a useful practice, (76) you shouldn’t mark up a book which isn’t yours. Librarians (77) lend you books expect you to keep them clean, and you should. If you decide that I am right about the usefulness of marking books, you will have to (78) them. There are three kinds of book owners. The first has all the standard sets and best sellers—unread, (79) . The second has a (80) many books—few of them read (81) , most of them dipped into, but all of them as clean and shiny as the day they were bought. The third has a few books or many every one of them (82) and dilapidated. Why is (83) a book indispensable to reading First, it keeps you awake. I mean wide (84) . In the second place, reading if it is active, is thinking, and thinking (85) express itself in words. Finally, writing helps you remember the thought you had, or the thoughts the author expressed.

A. marking up B. mark up C. to mark up D. to mark