поставить в множественное число: a book- a man- a room- a student- a box- a desk- a child- a city-
books
men - исключение
rooms
students
boxes
desks
children
cities - чередование y на i
a book-books
a man- men
a room-rooms
a student-students
a box-boxes
a desk-desks
a child-children
a city-cities