Are your teachers?变为单数形式.

Are your teachers?变为单数形式. we are english teachers(改单数形式) 变为单数形式 are Chinese buses These are Chiese buses.变为单数形式 They are oranges.(变为单数形式） Whose teachers are these They are ours改成单数形式 There are some women teachers over there改为单数形式 we are English teachers.（改为单数形式） Those are our teachers怎么改为单数形式急! they are your sons改为单数形式 Are these your cousins改为单数形式 are these your books?改为单数形式