This poem comes from the Silva distichorum moralium by François Oudin (1719).
E Libris Opes
Quid tibi de lusu superest, cum luseris? At quas
Legeris e libris, mens tibi servat opes.
The vocabulary is keyed to the DCC Latin Vocabulary list. There are two words in this poem that are not on the DCC list:
lūdo, lūdere: play, mock, ridicule
lūsus (lūsūs, m.): play, game, amusement
at: but, but yet
cum: with (prep. + abl.); when, since, although (conjunction + subj.)
dē: down from, about, concerning (+ abl.)
ex ē: out of, from (+ abl.)
legō legere lēgī lēctum: gather, choose, read
liber librī m.: book
mēns mentis f.: mind
ops opis f.: assistance, resources
qui quae quod: who, which, what / quis quid: who? what? which?
servō -āre: save, watch over
supersum -esse -fuī: be above; remain, survive
tū tuī tibi tē: you (sing.)