The plural form for the compound noun secretary-treasurer is secretry-treasurers.
The noun treasurer is made plural because only the treasurers are plural (not the number of secretarial posts each holds).
The plural possessive form is secretary-treasurers'.
Example: The secretary-treasurers' reports are due every six months.
The plural is inventories. The plural possessive is inventories'.
Taxes is the plural form of tax. The plural possessive is taxes'.
The singular possessive form of the noun cost is cost's.The plural form of the noun is costs.The plural possessive form is costs'.
The possessive form of the plural noun taxpayers is taxpayers'.The possessive form of the plural noun beneficiaries is beneficiaries'.
The plural form of the noun shareholder is shareholders.The plural possessive form is shareholders'.Example: The shareholders' votes are being counted.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is relatives. The plural possessive is relatives'.
The plural is lads. The plural possessive is lads'.
The plural form is echoes. The plural possessive is echoes'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is inches. The plural possessive is inches'.
The plural possessive of "Father" is, "Fathers"
The plural possessive of bandit is bandits'.
Studies' is the plural possessive of study.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.