"Moses supposes his toeses are roses" is a piece of English-language nonsense verse and a tongue-twister. It is a line from the song "Moses Supposes" in the 1952 musical film "Singin' in the Rain." The song was composed by Roger Edens, with lyrics by Betty Comden and Adolph Green. The song is performed by Gene Kelly and Donald O'Connor in the film.
Here's an example of how the line is used in the song:
Moses supposes his toeses are roses,
But Moses supposes erroneously,
For Moses he knowses his toeses aren't roses,
As Moses supposes his toeses to be.
