Repetition

is the mother of learning

enthusiasm,

zeal, learning

time, period,

age, world

command,

commandment

beginning,

foundation

man,

husband

vir

Find genitive singular for vir.

vir-i

Therefore, vir is the stem.

Second declension masculine nouns

that end in er or ir.

puer* (same stem)

ager(drop e for gen.)

liber(drop e for gen.)

magister(drop e for gen.)

vir*(same stem)

Give genitive singular.

puer - ?

vir  ?

pueri

viri

just add i

stem is same as nom. sing.

puer

vir

Give genitive singular.

magister

magistri

dropped 'e'

stem is magistr

Give genitive singular.

liber

libri

dropped 'e'

stem is libr

Give genitive singular.

ager

agri

dropped 'e'

stem is agr