Write the plurals: a factory, a tooth, a man, a wolf, a box, a knife, a cake, a city, a story, a woman, this desk. that toy. there is a room in flat. it is a child.

factories, teeth, men, wolves, boxes, knives, cakes, cities, stories, women, these desks;

Those toys. There are rooms in flat. They are children

A factory - factories

a tooth - teeth 

a man - men

a wolf - wolves

a box - boxes

a knife - knives 

a cake - cakes

a city - cities

a story - stories

a woman - women

this desk - those desks
That toy  - those toys

There is a room in a flat. - There are rooms in a flat.

It is a child - These are children.