You seem to be having trouble figuring out which word is the noun that needs to be the plural. Which thing do you have more of - twenty, year, or old? Twenty years is the modifier for old. You have two twenty year olds.
The plural form of the compound noun 'twenty year old' is
twenty year olds.
The plural form of the compound noun ten-year-old is ten-year-olds.
One ten year-old and two or more ten year-olds.
fifteen-year-olds
Bridges is the plural form of bridge.
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
There is no plural form for the word, countries. This word itself is a plural.
The plural of "she" is "they", so the plural of "she had" is "they had".
There is no plural form of pupae. Pupae is the plural form of pupa.
Bridges is the plural form of bridge.
There is no plural form for the word, countries. This word itself is a plural.
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
"Groceries" is the plural form of "grocery."
The plural form for the noun sergeant is sergeants; the plural possessive form is sergeants'.
It has no plural form.
The plural form of rung is rungs.
The plural form of mouth is mouths. The plural form of month is months. The Mounth is a range of hills in Scotland and does not have a plural form.
The plural of "she" is "they", so the plural of "she had" is "they had".
The plural form of the noun anniversary is anniversaries.The plural form of the church's anniversary is the church's anniversaries.The plural form of the noun church is churches.The plural possessive form is churches'.The plural form of church's anniversary is the churches' anniversaries.
The plural form of the noun rodeo is rodeos.The plural possessive form is rodeos'.Example: Of all the rodeos' prizes, this is the highest I've won.
There is no plural form of pupae. Pupae is the plural form of pupa.