there isnt a plural form of a.
The plural form is challenges.
Arguments is in the plural form for the singular noun argument.
"Daffodils" is the plural of "daffodil."
The plural form is digits; the singular form is digit.
The possessive form for the plural noun carcasses is carcasses'.
Bridges is the plural form of bridge.
"Groceries" is the plural form of "grocery."
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.
The plural form of "meter" is "meters."
The plural of crash is crashes.
It has no plural form.
The plural form for the noun sergeant is sergeants; the plural possessive form is sergeants'.
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".