NoDictionaries.com: You can find the word list for this fable online, and use it interactively (here are some tips on how to make best use of the tool).
READ OUT LOUD. Choose which marked text you prefer to practice with - macrons or accent marks - and read the text out loud until you feel comfortable and confident. Then, try reading the unmarked text at the bottom. It should be easy for you after practicing with the marked texts. :-)
MACRONS. Here is the text with macrons:
Agitābat quīdam equum et asinum onustōs sarcinīs. Asinus onere pressus rogāvit equum ut aliquā oneris parte sē levāret. Sed ille precēs comitis repudiāvit. Paulō post asinus languōre consūmptus in viā conruit et efflāvit animam. Agitātor igitur omnibus quās asinus portāverat sarcinīs atque īnsuper pelle eī dētrāctā equum onerāvit. Tum ille dēplōrāns fortūnam suam, "Quam stultē," inquit, "contempsī comitis precēs; nam sī illī obtemperāvissem, parvulum habērem onus, nunc gravissimum portō coāctus."
ACCENT MARKS. Here is the text with ecclesiastical accents, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
Agitábat quidam equum et ásinum onústos sárcinis. Ásinus ónere pressus rogávit equum ut áliqua óneris parte se leváret. Sed ille preces cómitis repudiávit. Paulo post ásinus languóre consúmptus in via cónruit et efflávit ánimam. Agitátor ígitur ómnibus quas ásinus portáverat sárcinis atque ínsuper pelle ei detrácta equum onerávit. Tum ille deplórans fortúnam suam, "Quam stulte," inquit, "contémpsi cómitis preces; nam si illi obtemperavíssem, párvulum habérem onus, nunc gravíssimum porto coáctus."
UNMARKED TEXT. Here is the unmarked text - after practicing with the marked text that you prefer, you should not have any trouble with the unmarked text:
Agitabat quidam equum et asinum onustos sarcinis. Asinus onere pressus rogavit equum ut aliqua oneris parte se levaret. Sed ille preces comitis repudiavit. Paulo post asinus languore consumptus in via conruit et efflavit animam. Agitator igitur omnibus quas asinus portaverat sarcinis atque insuper pelle ei detracta equum oneravit. Tum ille deplorans fortunam suam, "Quam stulte," inquit, "contempsi comitis preces; nam si illi obtemperavissem, parvulum haberem onus, nunc gravissimum porto coactus."
IMAGE. Here is an illustration for the story (image source) from a Renaissance edition of Aesop:
