zurückkommen
to come back
To return to a place or to a person that one has gone away from.
Wann kommst du aus dem Urlaub zurück?
When are you coming back from vacation?

to come back
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to come back
To return to a place or to a person that one has gone away from.
Wann kommst du aus dem Urlaub zurück?
When are you coming back from vacation?

'Zurückkommen' (to come back) is a separable verb. In a main clause, the prefix 'zurück' comes at the end. In subordinate clauses and in the infinitive with 'zu', the verb stays together.
Ich komme heute Abend spät zurück.
I am coming back late this evening.
Since 'kommen' (to come) describes movement, the perfect tense of 'zurückkommen' (to come back) is always formed with the auxiliary verb 'sein' (to be).
Sie ist gestern von ihrer Geschäftsreise zurückgekommen.
She came back from her business trip yesterday.
When referring to returning to a place, the verb is often combined with prepositions like 'aus' (from / out of), 'von' (from), or 'nach' (to): 'aus dem Urlaub zurückkommen' (to come back from vacation), 'von der Arbeit zurückkommen' (to come back from work), 'nach Hause zurückkommen' (to come back home).
Wir sind gerade erst aus Italien zurückgekommen.
We have only just come back from Italy.
If you want to bring up a topic again later, you use the fixed expression 'auf etwas zurückkommen' (to come back to something). The thing you come back to is in the accusative.
Können wir später auf Ihre Frage zurückkommen?
Can we come back to your question later?
In this figurative meaning, 'zurückkommen' (to come back) is often used for abstract things like feelings, memories, doubts, or pain that return.
Langsam kam die Erinnerung an den Unfall zurück.
Slowly, the memory of the accident came back.
to repeat / retrieve
'wiederholen' and 'zurückkommen' can both express that something happens again or becomes a topic again. 'wiederholen' is used when someone says, writes, or does something again, or when a situation occurs again. 'zurückkommen' is more suitable when a topic is taken up again later, or when a feeling, problem, or memory is back. Learners may confuse the words because both have to do with 'again'. A practical way to remember it: you repeat an action, but you come back to a topic.

Auf dieses Thema kommen wir nach der Pause noch einmal zurück.
We will come back to this topic after the break.
Die Lehrerin wiederholt die Frage, weil einige Schüler sie nicht verstanden haben.
The teacher repeats the question because some students did not understand it.