Translation:Yet, we were away for only two minutes.
It's still grammatically correct to place "only" at the end, even if it sounds awkward. I'm glad the version with "only" in the middle is the default translation, but the other one with "only" at the end should be accepted too.
- We only were away for two minutes
- We were only away for two minutes ^
- We were away only for two minutes
- We were away for only two minutes ^
- We were away for two minutes only
^ best versions
Is awkward syntax really "grammatically correct", even if the meaning of the sentence is more or less clear? IMO (In My Opinion), strange or unnatural ordering of words is bad grammar, because good syntax is part of good grammar.
The one sentence in this group which accurately states the thought is "We were away for only two minutes". The modifier is right in front of the thing modified. Can't be more clear than that.
Putting only at the end of the sentence violates the rule that adjectives come before the noun. Having it after the noun makes it sound like foreign grammar, e.g., French or German.
The further from "two minutes" that "only" gets, the more uncertainly is generated because this raises the question of whether "only" is an adjective modifying "two minutes" or an adverb modifying "were".
"We only were away..." is the worst: Does that mean "We only (and nobody else)" or We "only were" - and what does "only were" mean, exactly?
It's not that the general idea of the sentence is destroyed by playing around with the position of "only", but rather than the greatest clarity comes with the best grammar which comes with the best syntax.
That's only part of the grammatical structure. The basic format to express "only" (besides using "seulement") is [subject] ne [verb] que, e.g., nous ne sommes que = "We are only" (literally, "We are not but....").
(This exercise is made doubly complicated because Duo is using a reflexive compound verb, which explains why nous appears twice and why there are two verbs (auxiliary + past participle = sommes absentés)
You can see this structure in the exercise: nous ne nous sommes absentés que, which should be translated as "we were only away" or "we were away only".
The translation doesn't accurately reflect the French in a literal sense - it should be (if more literal) "We were only away for two minutes", since the ne...que surrounds the verb, and should require that "only" be viewed as an adverb modifying "were away", but Duo has changed it to an adjective modifying "two minutes".
If Duo's answer were translated back into French, then it might better be something like nous nous sommes absentés [pendant] seulement deux minutes" or more plainly nous étions absents seulement deux minutes.*
Anyway, it's the ne...que which creates the only. If this is the first introduction of this structure, Duo certainly picked a complicated way to do so.
que is placed in front of the element that is being restricted, here the number of minutes. It's not a typical
ne...pas structure. It's pretty cool that this exposes a layer of subtlety, the examples in the source highlight this quite well:
Il ne mange que des pâtes le samedi. versus
Il ne mange des pâtes que le samedi. Source: https://french.kwiziq.com/revision/grammar/how-to-use-restrictive-ne-que-with-simple-tenses-to-express-only-negative-expressions