поставьте глагол в скобках в past continuous или past indefinite tense:
an old ass was walking slowly along the road when he (to see) a dog, who (to lie) on the road and (to breathe) heavily. the ass (to stop) and (to ask) the dog why he (not to run), as dogs usually (to do). the dog (to answer) that he (to get) older and weaker, and his master (not to need) him any more. the dog (to ask) the ass where he (to go), and the ass (to say) he was going to the town of bremen , where he (to want) to become a town musician. he (to add) the people of bremen (to pay) good money for music, and (to invite) the dog to come with him. so they (to go) on together.
they (to walk) for some time, and then they (to meet) a cat, who (to sit) on the road and (to mew) very sadly. they (to ask) the cat what he (to do) there, and he 9to say) that he (not to know) what to do, because he (to get) older and older, and he (not to catch) mice as cats usually (to do). they (to go) off together for a long time, until they (to notice) a cock, who (to sit) on the fence and (to crow) very sadly. the cock (to say) he (to hide), because he (to know) that some guests (to come) soon to his master, and the master (to want) to cook the cock for dinner. so they (to go) together to the town of bremen.