"Are these your glasses?"
Translation:Це твої окуляри?
In English, "glasses" may refer either to sight glasses or drinking glasses, and without context it's impossible to know. Чашки and окуляри could both be the right answer, but only the latter is accepted.
Oh no. Ці is these indeed, but only when it determines the noun itself. In this context, however, it's just like "is it your glasses?". When you can put "it" instead of "this/that/these/those", you use neutral це: Це мої окуляри — these are my glasses (== it is my glasses); Ці окуляри — мої — these glasses are mine.