Learn Hardcore German: Woran denkst du jetzt? - What are you thinking about now?

Woran is a pronominal adverb formed by combining wo (where) + an (at/on). German generally prefers such pronominal adverbs over a separate preposition + was (an + was). So although An was denkst du jetzt? is grammatically possible, Woran denkst du jetzt? sounds more natural and idiomatic.

What case does an require after the verb denken, and why isn’t it visible in woran?

Denken an always takes the accusative case (e.g. an den Film, an das Konzert). With question words, German uses wer, was, etc., which do not change form in accusative vs. nominative—so you don’t explicitly see the accusative. In the pronominal adverb woran, the case is “hidden” inside the preposition, but you can be sure it’s accusative for denken an.

Why is du placed after denkst instead of before, and why is jetzt at the very end?

This is standard word order for a German W-question (a question introduced by wo-, wer, was, etc.). The pattern is:

Question word/pronominal adverb (Woran)
Finite verb (denkst)
Subject (du)
Remaining elements (object, time, manner, place)

Here jetzt is a time adverbial (“now”) and thus comes after the subject and any objects, which is why it’s at the very end.

Can I replace jetzt with gerade or nun, and do they change the meaning?

Yes:

jetzt = “now” (point in time)
gerade = “right now” / “just now” (more immediate)
nun = “now” (slightly more formal or literary)

Examples:

Woran denkst du jetzt? (What are you thinking of now?)
Woran denkst du gerade? (What are you thinking of right now?)
Woran denkst du nun? (What are you thinking of now?, literary tone)

Could I use the perfect tense here, like Woran hast du jetzt gedacht?

Yes. The perfect tense (Perfekt) emphasizes that the thought is completed or you’re asking about something you just finished thinking about.

Woran denkst du jetzt? (What are you thinking of now? – ongoing thought)
Woran hast du jetzt gedacht? (What did you just think about? – completed thought)

Is there any nuance between Woran denkst du jetzt? and Woran denkst du?

Adding jetzt specifically highlights “at this moment.” Without jetzt, the question still means “What are you thinking of?” but lacks the emphasis on “right now.” In conversation, you’d include jetzt if you want the learner to focus on the immediate moment.

Could I answer this question without repeating the preposition, e.g. just An mein Urlaub or do I need something else?

You must use the accusative after denken an, but you can drop the prepositional pronoun if the question word did the job. Example answer structures:

Ich denke jetzt an meinen Urlaub. (I’m thinking of my vacation now.)
An meinen Urlaub, if you’re echoing the question and omit the verb, might be understood in casual speech but is incomplete on its own. It’s better to complete the clause:
• (Ich denke) an meinen Urlaub!