"Are these your students?"
Translation:Це ваші студенти?
It is, but in sentences where existence or presense of something is stated ("There are new students in our group"). Also, in the possession structure ("У мене є").
(the last is, probably, even more important for Russian because—let a native speaker of Ukranian correct me—the Ukranian language has the verb мати, too, while Rusian иметь is hardly ever used for "to have" outside formal style and set structures)
This is my take on it. [I've only recently started learning Ukrainian, so please be wary, and seek further confirmation from more experienced learners!]
Це doesn't change when used as a subject, as it is here.
"What/who are these [things]?" "Are these [things] your students?" "These [things] are - my students/books/trees/etc...." This/these is the subject here, not "students".
Compare with "ці студенти їдять мед [apologies, my vocabulary is still very limited!]", where the students are the subject, and ці is describing them -- these students -- as opposed to those students, perhaps -- eat honey.