The word "manners" is the plural form of "manner".
Yes, the noun 'manners' is an abstract noun, a word for a concept.The noun 'manners' as the plural form of the noun 'manner' is a countable noun as a word for the way in which something is done or something happens; an outward way of behaving toward others.The noun 'manners' is an uncountable noun as a word for social deportment; a socially acceptable way of behaving.
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.
The plural form is metres.