The word 'a' has no plural form; the word 'a' or 'an' specifically means one. If you want to show more than one of the noun, you use other words such a couple, a few, some, three, five, many, etc.
aes
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.
The plural form of him, her, or it is them. (objective pronouns)
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 form of the demonstrative pronoun 'that' is those.
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 parenthesis is parentheses.
The plural form of boy is boys.