Thus, the joke unfolds: a donkey (an ass) gets a passport so that it can be recognized as an ass abroad . More precisely, the pun plays on “ass” as a noun for the animal and “abroad” sounding like “a broad” (a slang term for a woman, though less common today) or simply “overseas.” The classic punchline is: “So he could be an ass abroad.”
In other words, the passport allows the donkey to officially be what it already is—an ass—but in a foreign country. The humor stems from the double meaning of “ass” (donkey / foolish person) and the idea that travel documents certify a status that is normally inherent or ridiculous. why did the donkey get a passport answer key
If your teacher or puzzle expects a one-line answer: Thus, the joke unfolds: a donkey (an ass)