Сравни произношение и написание однокоренных слов: весть - [в,эс,т,] вестник - [в,эс,н,ик] известный - [изв,эсный,].

We go to school in the morning.
Do you go to school in the morning?
Do you go to school or to the park in the morning?
Where do you go in the morning?
When do you go to school?
We go to school in the morning, don't we?

Now six friends are students.
Are six friends students now?
Are six friends students or pupils now?
How many friends are students now?
When are six friends students? звучит каряво, но если бы я поставила вопрос к подлежащему, то получился бы другой вид вопроса, не специальный
Now six friends are students, aren't they?