SOURCE: This is a Latin prose version of Babrius's Greek verse fables, as published by Jean François Boissonade in 1844; the book is available at GoogleBooks. This is fable 60 in Boissonade's edition; for other versions, see Perry 167.
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:
In ollam iusculi plēnam, quae carēbat operculō, mūs cecidit. Et suffōcātus adipe, iamque expīrāns animam, Ēdī, inquit, bibīque, et cunctīs implēvī mē cibīs. Mihi tempus est morī." Helluo fiēs mūs inter hominēs, sī quae nocent dulcia nōn rēspuēs.
ACCENT MARKS. Here is the text with accent marks, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
In ollam iúsculi plenam, quae carébat opérculo, mus cécidit. Et suffocátus ádipe, iamque expírans ánimam, Edi, inquit, bibíque, et cunctis implévi me cibis. Mihi tempus est mori." Hélluo fies mus inter hómines, si quae nocent dúlcia non réspues.
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:
quae carebat operculo,
Et suffocatus adipe,
iamque expirans animam,
Edi, inquit, bibique,
et cunctis implevi me cibis.
Mihi tempus est mori."
fies mus inter homines,
si quae nocent dulcia
IMAGE. Here is an illustration for the story (image source) showing a mouse swimming - it actually comes from the Tenniel illustrations to the story of Alice in Wonderland!