When I initially read the sentence I could reasonably expect that there were possibly multiple bookshelves in the room. One of these is by the desk. Any other bookshelves are in different locations, perhaps over by the window. Hence the bookshelf by the desk makes perfect sense if you wish to direct the person to a particular shelf. It’s just a case of narrowing down the location.
If there were other identifiers it wouldn’t be necessary to include the desk as a descriptor. One could say ‘The book is on the blue bookshelf’ for example.
Alternatively one could say ‘the bookshelf by the desk’ if there were only one bookshelf but it’s an unnecessary addition and might only be useful if it were a very small shelf and hardly noticeable.
Well, they do say “on line” where we would say “in line”, so I suppose so. However, if the OP is English, I wasn’t aware of it…and besides, we all know how much they screwed up the language anyway before we came along and fixed it.
Obviously. If you were a cunning linguist you’d have better things to do than to be posting here.
I must admit I pictured one bookcase next to the desk and didn’t think of how many shelves it might have. Probably because I grew up with bookcases and never single shelves on the wall.
[spoiler]1, normally. If there were more than one I would expect you to say "one of those bookcases next to the desk, since there could be one on either side. OTOH, you might say simply “the” in that case, perhaps if you were pointing or gesturing to indicate which of the two you meant.
It would be possible, if there were only one bookcase to say *in a bookcase next to the desk, but then the context might be that you are sending the listener to get the book, in an unfamiliar room, in the sense of: “next to the desk you’ll find a bookcase…”[/spoiler]
One. “The” is a definite article, so there’s only one bookshelf next to the desk.
(there’s no way to tell how many there are in the room - but only one “next to the desk.”
If there were multiple bookshelves next to the desk, it would be “The book I’m talking about is in a bookshelf next the desk.” (or “a bookshelf near” or “one of the bookshelves next to”)
