How can you tell if an indefinite pronoun is singular?

Some indefinite pronouns are singular only, some are plural only, and some function as both singular and plural. Examples:

SINGULAR

another

anybody

anyone

anything

each

either

enough

everybody

everyone

everything

less

little

much

neither

nobody

no one

nothing

one

other

somebody

someone

something

PLURAL

both

few

fewer

many

others

several

they (as a Word for people in general)

SINGULAR or PLURAL

all

any

more

most

none

some

such