"I announce my book."
Translation:Ich gebe mein Buch bekannt.
I'm not sure it's explained in any particular lesson on Duolingo, unfortunately, but you will find many explanations on the internet and in textbooks.
The reason is that German has separable verbs. This is kind of like how in English certain verbs get their meaning from a combination of words, e.g. "to turn on" has a different meaning to "to turn", and when used in a sentence that extra word can end up at the end: "I turn the television on".
The verb in this example is ankündigen = "to announce". This 'dictionary form' of the verb is called the infinitive, and it's written together as one word. The 'separable' nature of such verbs shows itself in certain sentence structures, where the prefix gets bumped to the end (as in Duo's example).
These prefixes often, but not always, look like prepositions. So, when you see what looks like a preposition hanging out alone at the end of a sentence, it's likely a separable verb prefix.
Here are some examples of sentences using this verb, so you can see how the separable prefix behaves in different situations. If there's a sentence structure that's unfamiliar to you, keep going through the Duolingo lessons - it'll be taught later:
Ich kündige mein Buch an = "I announce my book"
Past tense (perfect):
Ich habe mein Buch angekündigt = "I have announced my book"
Past tense (simple):
Ich kündigte mein Buch an = "I announced my book"
Ich werde mein Buch ankündigen = "I will announce my book"
Present tense, in a subordinate clause:
Ich bin gespannt, weil ich mein Buch ankündige = "I am excited because I am announcing my book"
Tip: You can find all the forms of a verb on conjugation sites like Canoo.net.
One odd thing about this example is that I and apparently a lot of other people see "Ich kündige mein Buch an" as the correct translation for the quiz but the translation in the discussion is "Ich gebe mein Buch bekannt." Tinycards has bekannt for this skill but not ankündigen which might show up in the future. It seems like Duo should give the same best answer in both places. And it would be better if Tinycards gave "announced" as another possible translation for bekannt instead of just "known."
The verb being used here is the separable verb "bekanntgeben" which means to announce". The verb "bekannt"is a different verb and means "to know".
I find that the Tinycard decks tend to not include important words for lessons, use translations that are not used in the lesson, or use translations that are not the most likely to be used. They do lack consistency with Duolingo in many ways. I do like the interface though, and generally use it to make my own decks.
So while I agree about some of the critiques about Tinycards and consistency, "announce" is NOT another translation for the word "bekannt".
I am so fond of seeing a new seperable verb not announed as new - presumably because I've seen both "kündigen" and "an" as words, and Duolingo's programmers simply don't understand that the actual word is "an/kündigen", that just happens to be written in widely seperated parts most of the time.
I also wonder whether bekannt/geben (which I tried to use) would in fact have been legitimate. Not that I'm privileged to know that, of course; we no longer get to see anything but the 'best' snicker answer - the one involving a verb we've never seen before, that presumably we'll randomly guess out of nowhere.
It would be nice to be allowed to know what the correct form of bekannt/geben would actually have been. (I'm presuming is legit, but I made a small error which was 'corrected' by telling me to use this other word I've never heard of.)
It's a good thing Duolingo is free, because it's very often worth exactly what we pay for it.
For what it's worth, i can attest to being unpleasantly surprised many times by unannounced vocabulary suddenly showing up. It is shocking in a way that adds friction to my learning experience & desire to practice... unfortunate that someone on the design team hasn't looked into correcting it
Another point of view: I actually don't mind it when Duo springs new vocab on us out of the blue. It makes the new word surprising and memorable. Also, that's how you learn new words in real life. If I get that particular question wrong the first time I see it, no big deal. Das neue Wort ist es wert.
There appear to be two correct answers:
Ich kündige mein Buch an.
Ich gebe mein Buch bekannt.
Both contain separable verbs. The first, ankündigen, is described in terrific detail by by az_p. The second is bekanntgeben which work in the same manner.
My question is whether there are circumstances where one would be preferred over the other?
Not mentioned in the comments so far, but accepted for me is "Ich stelle mein Buck vor", using etw. vorstellen - introduce as the verb. After reading through the translations and some examples, I think the other two popularly accepted answers (bekanntgeben, ankündigen) are better than the answer I got away with.