Usted anuncio el hotel???
I am a bit mystified by this statement, 'You announced the hotel' It just doesn't seem a statement that would be used in everyday English language. I know this is a learning programme but there does seem to be a lot of similar odd pieces of English in Duolingo which is quite discouraging when trying to learn a new language.
I'm going to gain the unpopular vote here, but I think the nonsensical sentences are actually a good idea. They are still grammatically correct in Spanish and because of their silliness, they actually become memorable. Whether it's "La gata bebe cerveza" or "La mujer come manzanas", the construct remains the same. By doing so, it allows the student to think outside the box and not just memorize how to say things, but actually learn to construct sentences. Just my opinion of course.
Gumbee, that is a good explanation and I think it works in some cases. But for example when a sentence is read to me that I have to write down in spanish, it can be hard to hear what exactly the words are, probably partially because the automatic pronunciation is not optimal. In those cases it would be helpful to be able use common sense to infer the words that I am in doubt about. With these kinds of sentences it is impossible.
I agree that this is very discouraging. I came across sentences like "La araña come pan" in the beginning and was quite confused why I should learn this. I remember when using Rosetta Stone that almost all sentences that I was taught in that program were useful in some way in everyday conversations.
Personally, I would prefer to learn Spanish phrases that make sense and can be lodged in my memory bank. It must be easier to recall a sensible sentence that Spanish people will understand rather than struggling with words that I have to start thinking about. After all, we all learn to speak in the first place by imitation!