Exercise 1.
a dog - dogs
a ball - balls
a desk - desks
a horse - horses
a fact - facts
a nose - noses
a lip - lips
a mother - mothers
a father - fathers
a brother - brothers
a pen - pens
a pencil - pencils
a flower - flowers
a kid - kids
a pupil - pupils
a lion - lions
an elephant - elephants
an apple - apples
Exercise 2.
a class - classes
a box - boxes
a bus - buses
a match - matches
a bush - bushes
a wish - wishes
a loss - losses
a tomato - tomatoes
a princess - princesses
a boss - bosses
an ostrich - ostriches
a brush - brushes
a witch - witches
a fox - foxes
a dish - dishes
a hero - heroes
an address - addresses
a glass - glasses
Exercise 3.
a cry - cries
a lady - ladies
a baby - babies
a puppy - puppies
a strawberry - strawberries
a cherry - cherries
a reply - replies
a party - parties
a spy - spies
the sky - skies
a city - cities
a country - countries
a lorry - lorries
a doggy - doggies
a poppy - poppies
a story - stories
an enemy - enemies
a family - families
