Translation:I remembered where my keys are, at last!
We didn't have that translation but it's been added. Many thanks for the input.
"Finally, I remembered where my keys are." is shown as a correct translation. Barring any other errors, it should have been accepted. If you have this sentence again and encounter a problem please send a screenshot.
I remembered where my keys WERE at last. I remember where my keys are at last.
The correct answers are as follows with explanations:
"I remembered where my keys were, at last."
"I remembered where my keys are, at last."
In Greek "θημήθηκα" the main verb is past tense so the English needs to be past tense. "remembered"
Although "είναι" in Greek is present tense, English common usage uses the past tense because the main verb (here "remembered") is in the past tense. So we get: "I remembered where my keys were..."
"I remembered where my keys are at last."
The Greek "Θυμήθηκα" which is the main verb is past tense so the Engish is also past tense remembered.
The Greek είναι is present tense and modern usage now also uses English present tense are.
Hmmm...I can finally remember where that hotel in Paris was where I stayed last year. In (American, at least) English it's fine to say "I remember finally where the hotel was" OR "I remember finally where the hotel is." (As the hotel presumably hasn't moved. Nor have the keys, likely, since I started trying to find them.) This seems fine in English, but I wonder about its Greek: "I remembered finally that my keys ARE in my office, and I'll get them tomorrow when I go back in to work."
As explained above it's normal and correct to use a past tense secondary verb if the main verb is pst tense. It's common to say e.g. "He said his name was Henry." why was? has his name changed? No, that's just a convention of the language.
Anyway, my answer was marked wrong: "I remembered where are my keys, finally."
Yes, I'm afraid you used the question form of word order although this is not a question. You needed "I remember where my keys are, finally." It's not unusually for someone one to misconstrue "where" as a question word...it is not. It just refers to the "place".