The singular possessive form is week's.
The singular possessive form of "classmate" is "classmate's."
The possessive form is Amos's.
The singular possessive form of "gypsy" is "gypsy's."
The singular possessive form of "countries" is "country's".
The singular possessive form of county is county's.
singular possessive: boy'splural possessive: boys'
The singular possessive form is aircraft's.
The singular possessive form is speculum's.
The singular possessive form is contralto's.
The singular possessive form is frontiersman's.
The singular possessive form of the word "jury" is "jury's."