One little orphan had roast beef, the other had none.
One little orphan went to market, the other stayed home. Wait a second.
Orphan Nursery Rhyme Interruption
Explanation
Explain Bear
Listen up, dummy! This joke is funny because it starts like a nursery rhyme, see? But then it stops all of a sudden, like the person telling the rhyme is realizing they messed it up. It's like when you try to remember the alphabet and forget what comes after "L".