Here’s a test to see if you understood something that you read: “State it in your own words.”
If, when you are asked to explain what the author means by a particular sentence, all you can do is repeat his very words, with some minor alterations in their order, you had better suspect that you do not know what he means.
Ideally, you should be able to say the same thing in totally different words.
If you cannot get away at all from the author’s words, it shows that only words have passed from him to you, not thought or knowledge. You know his words, not his mind. He was trying to communicate knowledge, and all you received was words.
— How to Read a Book by Mortimer J. Adler and Charles van Doren