This is from The Book of Sun-Dials by Mrs. Alfred Gatty [aka Margaret Scott Gatty], which you can read online at this University of Pennsylvania website.
Hora Volat
Prima fuit, praesens volat, ultima quando sonabit
Haec latet; imprudens ergo, caveto tibi.
The vocabulary is keyed to the DCC Latin Vocabulary list. There are two words in this poem that are not on the DCC list:
imprūdens (imprūdentis): foolish, reckless
volō, volāre: fly
caveō cavēre cāvī cautum: be on guard, beware
ergo: therefore
hic haec hoc: this; hōc: on this account
hōra -ae f.: hour
praesēns -ntis: present, in person, ready
prīmus -a -um: first; adv. prīmum: at first, firstly
quandō: when?; since; si quando: if ever
sonō sonāre sonuī sonitum: sound, resound
sum, esse, fuī: be, exist
tū tuī tibi tē: you (sing.)
ūltimus -a -um: farthest, final, last, ultimate