Classify the following into masculine, Feminine, common, Neuter
Gentleman, doctor, chair, waitress, manager, granddaughter, mare, monk, child, Hunter, students, teacher, valley, book, ewe, person, tree.
masculine - gentleman, doctor, manager, monk, hunter, students
Feminine - mare, granddaughter, waitress, ewe
common - chair, child, teacher, person
Neuter - valley, book, tree