The noun 'knowledge' is a mass (uncountable) noun, a word that has no plural form. The noun 'knowledge' is a type of aggregate noun, a word representing an indefinite number of elements.
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.
The plural of "tree" is "trees." In English, most nouns form their plural by adding the letter "s" to the singular form. This is a regular plural noun formation rule.
There is no plural form for the word, countries. This word itself is a plural.
There is no plural form of pupae. Pupae is the plural form of pupa.
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 "was" is "were."
The plural form of "I" is "we."
The plural form of "is" is "are."
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.
"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 the demonstrative pronoun 'that' is those.
Trenches is the plural form.
The plural form is metres.