In general, to form the plural add 's' or 'es' to the singular
E.g
A boy boys
A girl girls
A pen pens
A dress dresses
A watch watches
An address addresses
There are nouns that change in plural
e.g
An ox oxen
A man men
A woman women
A child children
A tooth teeth
A foot feet

The 'f' becomes 'v' in the following
Knife knives
Leaf leaves
Wife wives
'They' is the plural of(he, she , it)
e.g
She is a girl They are girls
He is a man they are men

 
SANDRA,
Thank u honey for your topic