Illiterate is usually an adjective, and in this sense does not have a plural form. The noun for illiterate is illiteracy, for which the plural can be illiteracies, but it is awkward. Illiterate is sometimes used as a noun to describe an illiterate person, in which case the plural would be illiterates, e.g. as in the insult, "You are a bunch of illiterates!"
uneducated, illiterate
uneducated, illiterate
There is no plural form. Do and Do not are verbs
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
The plural form of "is" is "are."
The plural form of "I" is "we."
The plural form of "was" is "were."
"Groceries" is the plural form of "grocery."
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
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 form of the demonstrative pronoun 'that' is those.