The plural form of the noun trio is trios.
The plural possessive form is trios'.
Example: Both trios' members also sing well as solo performers.
The plural possessive of "trio" is "trios'" when indicating ownership or possession by multiple trios.
The possessive form of the singular noun trio is trio's.example: The trio's performance received thunderous applause.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural form is founders. The plural possessive is founders'.
The plural form for the noun sergeant is sergeants; the plural possessive form is sergeants'.
The singular possessive form for the noun knife is knife's.The plural form is knives; the plural possessive form is knives'.
The noun 'sister' is not plural and is not possessive.The plural form is sisters.The possessive form is sister's.The plural possessive form is sisters'.
The singular form is goose; the singular possessive form is goose's.The plural form is geese; the plural possessive form is geese's.
The plural possessive form of "cherubim" is "cherubim's."
The plural possessive form of "reply" is "replies'".
The plural form is valleys. The plural possessive is valleys'.
The plural form is squirrels. The plural possessive is squirrels'.