Translation:My father went to a castle yesterday.
I heard from many native speakers that "ging" (simple past tense, das Präteritum in general) is used mainly in written language, but is rarely used in spoken language.
Is that right?
For example, while people speak they say "Ich bin gegangen", But when it is written, they may write "Ich ging"
Is this true?
If you use "in" in the meaning of "into" it goes with Akkusativ, in the meaning of "within", it goes with Dativ. There are several other prepositions that do likewise :(
As far as I know, "mit" goes always with Dativ, whereas e g. "an" goes either with Akk. ("Ich hänge das Bild an die Wand"), or with Dat. ("Das Bild hängt an der Wand").
Why is the "gestern" after the verb? Duo did not accept if it was the last word in the sentence. (and not was the first time when Duo did not accept my answer if the time was not after the verb)
English sentences have quite a rigid word order: if not first, the time adverb usually goes last (cf https://dictionary.cambridge.org/grammar/british-grammar/about-adjectives-and-adverbs/adverbs-and-adverb-phrases-position)
The "correct" English answer My father went to a castle yesterdaywould be accepted by most native speakers, myself included, but it is ambiguous. Going to a castle does not necessarily mean going inside it.