So demonstrative pronouns are the same pronouns that are also used fordemonstrative adjectives - this, that, these and those. ... The demonstativepronoun takes the place of the noun phrase. The demonstrative adjectivemodifies the noun and is always followed by the noun.
A possessive pronoun does show ownership, but it does not come before a noun or in a noun phrase. ... Remember, possessive pronouns are used to replace the noun. Possessive adjectives are used to describe the noun. Notice that some forms of the possessive adjective and possessive pronoun are the same (his, its).