Translation:The boy is picking up a blue book.
No one would ever say that sentence for any reason. It doesn't have an article in front of boy and it also implies there is a boy and he raisng a book. Like he adopted a baby book and is now raising it to book adulthood.
Boy raises a blue book sounds strange to me as a native English speaker. If you said, "The boy holds up a blue book", that would be ok. The other two sentences are correct.
although you can, for example, "raise a blue flag". Would that still be "podnosić"? Also, with a bit more context, something like "the boy raises a blue book above his head" would also work.
For the flag - I think I'd go with "wznosić". For the other one, I guess "podnosić" would be ok, "wznosić" as well.
Well, if said flag was on a mast rather than being held in hands, I would still be ok with „podnosić”.
Lica98- people are objecting to "raises" as they feel it sounds like the boy is raising the book as you might bring up a child. However, I agree that it can work in the right context eg "the boy raises the (holy) book (and everyone falls to their knees) :-) . I also think "lifts up" works.
Can podnosić be used to talk about shopping? e.g "I'll pick up some eggs on my way home"