Given an entity, a before event, an after event, and an attribute related to the entity, generate a sentence as output. Your sentence should show the changes in the attribute of the entity.

entity: necklace
before: unworn
after: worn
attr: placement
placement of necklace was unworn before and worn afterwards

entity: yarn
before: long
after: wrapped
attr: shape
shape of yarn was long before and wrapped afterwards

entity: air pump
before: bought
after: owned by person
attr: ownership
ownership of air pump was bought before and owned by the person afterwards