I was practicing my Russian with a friend when she wrote the following:
"когда я пришёл на фестиваль, народу было не очень много, но позже очереди за едой стали слишком длинные."
In this situation, why is длинные used instead of длинными?
I asked her about it, and she said using длинными wouldn't sound right here.
I appreciate your help with this matter. Thank you!
You can use both the nominative and the instrumental with adjective predicates with быть, стать, оказаться.
The difference between the two is stylistic: the nominative is a little bit more vernacular, while the instrumental is a little bit more formal and bookish. In this particular phrase, the difference is so subtle that you could use either case in speech, and nobody would bat an eye.
There are several contexts where one case is preferred over the other:
When the adjective is thematic and starts the sentence, the nominative is preferred: Красивая она стала — глаз не оторвать!
When the adjective defines the object of a proximal possession clause, the nominative is preferred: Глаза у него стали широкие, как блюдца
When the adjective defines the object of a pronominal possession clause, the instrumental is preferred: Его глаза стали широкими, как блюдца
But even in these cases, it's still OK to replace one case with the other.
im not sure that im right, but in my hear second version is "more" right. The first one "очереди за едой стали слишком длинные" gives more focus on "очереди за едой" as main the thing in the narrative. So, the nominative case gives more attention to the specific detail, then the instrumental case. So, the first variant is ok, if you want to tell about definitely queue, maybe it is same as to say "the queue", and other cases give "a queue". But the sentence has three parts : когда я пришел на фестиваль - 1, народу было не очень много - 2, но позже очереди за едой стали слишком длинные - 3, - it looks too long for a message about "очереди за едой" and looks boring because contain also information about self. But if you use the instrumental case, the story's focus moved from a queue to self, and it has become a story about self, not about a queue. Also, you can continue the story(about self) after, but if you use the nominative this story looks as complete message.
The same:
Его глаза стали широкими, как блюдца - story about him
Его глаза стали широкие, как блюдца - story about his eyes
