"When had you entered the museum?"
Translation:Quando eri entrata nel museo?
"Quando eri entrato nel museo" was accepted July 2020. The first time I answered "il museo" rather than "nel museo" and it was marked wrong. At first I thought the problem was gender, but I took a second look and found the real problem. Perhaps there was an error in your answer as in mine or maybe Duolingo has changed its program.
The simple answer is that we're talking about entering the museum, and in + il = nel.
The more complicated answer involves the use of the definite article in Italian, and how it's different from English. If you were talking about going to an unspecified museum, you might say in museo, but if you're asking a fellow museum-goer at the Museum of X when they crossed the turnstiles to enter said museum, you'd say nel.
"Quando eri entrato al museo" was accepted on 3 October 2020. I used "al" because I had remembered "arrivare al museo", but I suppose that "eri entrato al museo" is wrong and should be "entrato nel museo" -- even though duolingo accepted "entrato al museo" in the case of my translation of this sentence...
I answered this question two years ago. To recap: The Italian sentence as written applies if you're talking to a woman. A sentence with entrato applies if you're talking to a man. They're not interchangeable, but without additional information you can't tell which is the correct translation of the English sentence, which doesn't specify the sex of the person being talked to.
says entrare takes avere. is that wrong?
I don't know about most of the time, but they're definitely unreliable and should be avoided as much as possible. They provide several possible translations of the word that you hover over, but those translations may be for completely different uses of the word than in the sentence you're studying.