Translation:She sometimes goes traveling alone by herself.
I put "She sometimes travel by herself." and got it wrong. What!? That is the right answer, but just another way to say it.
It isn't, actually. They should both be accepted, 一个人 and 自己一个人, together with other acceptable alternatives like 独自.
The English translation sounds a bit redundant. I don't think I would ever say "alone by myself" even though it is grammatically correct.
The English sentence tries to translate the Chinese as directly as possible, but in my opinion this goes too far here, as the English sentence becomes wrong. "She sometimes goes traveling alone by herself." may be okay as an accepted translation, but should definitely not be the default solution.
Eric Carmen's "All By Myself" bother you, too? ;-p
I really hate this app for being so OCD. Same problem here like Annie describes
I have noticed that Duo's translations tend to lean towards British English usage, and "on one's own" (in this case, "on her own") is the standard way of saying in British English what Americans would normally express as "alone." Both "alone" and "by herself" are correct here. If you used one of these and are still getting it wrong, please report it so that DL can add it to their list of correct answers - each of which apparently must be entered separately, by hand. (This is why it sometimes takes Duo a while to check your answer - it means it is going through all thr available possibilities, and yours my be towards the bottom of the list.)
I get that they're trying to teach us two words for the same concept: 一个人 and 自己. The problem is they strictly have us switch the order while asking us to use slightly incorrect English to do it. '自己一个人' means 'by oneself alone' but they count it wrong if I don't reverse the order to 'alone by oneself' I'm worried it's teaching me to switch the translations this way too
I concentrate more on the sentence structure in CHINESE. Yes, the translation into English is sometimes redundant and if you follow it closely, you may compromise your English grammar. I believe creators of DL are learning to improve their English in the same way we are learning Chinese.