I can confirm that it is accusative. I cannot confirm whether it showed up in a dative exercise by accident or as intentional review to keep you on your toes. Since "euch" is both the accusative and dative form of "ihr", perhaps this sentence to be mistakenly placed in a dative section. Good recognition of the accusative usage.
Sie mag euch. = She likes you (when you are speaking to more than one person)
Sie mag dich. = She likes you (when you are speaking to just one person)
euch is the accusative form of ihr (you, plural / y'all / you guys), and dich is the accusative form of du (you, singular).
So do all intransitive verbs take the dative case?
Most intransitive verbs do not take any object at all, in any case.
There are some verbs that take an object in the dative case (e.g. helfen, danken, folgen, gefallen, gehören, antworten) which have to be learned by heart. Whether to call those verbs transitive (since they take an object) or not (since they don't take an accusative object) is a matter of definition.
which on-line dictionary do you like best?
As you can tell, I used confusing grammatical terms for stating my question. Thank you for responding anyway.
Here is a link for others who may be struggling like I am with this (although I hope there are only a few at best)
I started to assume mögen must be one of the verbs that triggers the dative since this is in the dative exercises. Glad I checked the comments to see it is actually "euch" in the accusative. It's funny how much your success in Duolingo depends on the discussion forums. Duo is just like, "Let them figure it out amongst themselves."
You were supposed to know from the verb form :)
Sie mag euch. = She likes you.
Sie mögen euch. = They like you.
sie "they" almost always has a verb form ending in -en.
sie "she" almost always has a verb form ending in -t (in the present tense); with a handful of exceptions including most modal verbs, which have no ending at all for sie.
It's a bit like how in English, "the sheep runs away" and "the sheep run away" show by their verb how many sheep there are, and the learner would be supposed to know that "the sheep runs away" means one sheep but "the sheep run away" means several sheep.
Why not 'Sie magt euch'.
Historical reasons. The same ones that are responsible, in English, for saying "she may come" and not "she mays come".
(Basically, the verb originated in a past-tense form, and strong verbs do not have an ending for ich or er/sie/es in the past tense -- so it's ich mag and er mag with no ending, just like ich lag and er lag as the past tense of liegen = I lay, he lay.)
Methinks "Sie mag dich", "Sie mögen dich", and "Sie mögen euch" are more common than Sie mag euch.
Also, this is an accusative verb in a dative lesson, which is confusing. I don't have a problem with multiple sections being tested at the same time, but this is a free platform, and, while being able to select two lessons and get quizzed on both simultaneously would be great, I suspect it'd be complicated and expensive to program. So, I'm here to review verbs that take the dative case because the construction is odd and the meanings idiomatic. Throwing in an accusative verb because it uses an accusative/dative crossover pronoun doesn't seem like the best choice.
No -- "du" is nominative case but here you need the accusative case, as the object of "mag". (Just as you couldn't say "He likes I" or "Do you like he?" or "They don't like we" in English.)
So it would have to be "Sie mag dich." if you wanted to use the informal singular form.