There is no plural form of nine. Nine is a number itself, which can describe something that there are nine of.
The plural is toothpastes.
Much does not have a plural form.
Wizards is the plural form.
The plural form for the noun memo is memos.
The plural form for the singular noun dot is dots.
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."
"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.
Trenches is the plural form.
The plural form is metres.