Поставьте следующие существительные во множестве ноет число a pen.a class.a story.a road.a day.a cat.a bush.a desk.a table.a plate.a fox.a room.a lady.a knife.a chair.a bus.a hero.a match.a way.a house.a family.a flag.a town.a country.a lion.a park.a play.a dictionary.a thief.a key.

A pen - pens
a class - classes
a story - stories
a road - roads
a day - days
a cat - cats
a bush - bushes 
a desk - desks
a table - tables
a plate - plates
a fox - foxes 
a room - rooms
a lady - ladies
a knife - knives
a chair - chairs
a bus - busses 
a hero - heroes
a match - matches
a way - ways
a house - houses
a family - families
a flag - flags
a town - towns
a country - countries
a lion - lions
a park- parks
a play - plays
a dictionary - dictionaries
a thief - thieves 
a key - keys