The singular possessive form for the noun gentleman is gentleman's.
Example: The gentleman's limo awaits at yonder curb.
The singular possessive form is week's.
The singular possessive form is classmate's.
The possessive form is Amos's.
The plural form for the noun gentleman is gentlemen.The plural possessive form is gentlemen's.
The singular possessive form for the noun gypsy is gypsy's.
The singular possessive form for country is county's.
The singular form for the plural noun countries is country; the singular possessive form is country's.
singular possessive: boy'splural possessive: boys'
The singular possessive form is aircraft's.
The singular possessive form is frontiersman's.
The singular possessive form is contralto's.
The singular possessive form is speculum's.