"Do you understand this book?"
Translation:Ты понимаешь эту книгу?
I consider that yes. Have you reported? But pay attention, it must be Понимаешь :)
How do I report it now? Once I've left the question I don't seem to have the option to report anymore.
Oh, you should have reported while you were on that question. It's okay, others may see this discussion and report. :)
OK, I wasn't confident enough to report it without asking first and I didn't realize I wouldn't be able to report later. Should I start reporting even if I'm not absolutely sure?
Well, you can still report, and the contributors will decide themselves to consider your report or not, and they will also answer your questions, or tell you why your report is incorrect. :)
From what I can find, книжку either means a book or a ruminant's second stomach, called a psalterium in English.
"Вы" is plural, and also is used as a polite singular form. "Ты" is informal singular, used with close friends and relations. They correspond exactly to German "sie" and "du".
Is there a way to tell if the sentence is polite or informal? I was told I should've used ты even though it didn't mark it wrong?