This little poem comes from Disticha de Educatione of Urbano Appendini, published in 1834; you can see the whole book at Google Books.
Vires Viribus Adde
Ceu duri maneant in sera aetate labores,
Nunc vires iuvenis viribus adde novas.
The vocabulary is keyed to the DCC Latin Vocabulary list. There is only one word in this poem that is not on the DCC list:
ceu: as, like, just as
sērus, -a, -um: late, slow
addō -dere -didī -ditum: give to
aetās -tātis f.: age, time of life
dūrus -a -um: hard, tough, harsh
in: in, on (+ abl.); into, onto (+ acc)
iuvenis -is m.: youth
labor -ōris m.: toil, exertion
maneō manēre mānsī mānsum: remain
novus -a -um: new
nunc: now
vīs f.: force; (acc.) vim, (abl.) vī; (pl.) vīrēs, strength
