The simple basic rule is :
in the singular - add 's (apostrophe s) eg the boy's ball or the ball of the boy
in the plural - add ' (apostrophe only) eg the boys' ball or the ball of the boys.
There...
It can be a noun, and it can be a verb. It is a noun in the following examples:'My bouquet was in the form of a crown.''He did not know the correct form of behaviour.'
To make a plural noun add -s to nouns. eg boys, tables, books. For nouns that end in -y change the y to i and add -es. eg baby - babies, lady - ladies.To make a possessive form add 's (apostrophe s)...
The plural forms of the following words are: wood: The noun wood is a non-count (mass) noun; a word for a substance. Nouns for substances are used in the plural for 'types of' only; for example two...