1)We are in Moscow.
Are we in Moscow? (General)
Are we in Moscow or Kiev? (Alternative)
Why are we in Moscow? (Special)
Who is in Moscow? (Subject)
We are in Moscow, aren't we?
2)My friend must go to school.
Must my friend go to school?
Must my friend go to school or to cinema?
Why must my friend go to school?
Who must go to school?
My friend must go to school, mustn't he?
3) К сожалению, слова parend в английском нет.