Does the subject want to ask "the reason why an old man borrows books from the library every week, but always turns to the 30th to borrow books"? Reading plan, personal preference.

1. Reading plan: The elderly have a reading plan and have decided to read only page 30 every week. This is because I want to read more different books in a limited time, or because I want to keep reading fresh.

2. Personal preference: The elderly have special interest or emotional connection with 30 pages.