Smelled and smelt are both correct past tense and past participle forms of smell. Smelled is more common in American ...

 Favourite and favorite have the same meaning. The only difference is spelling. Favourite is the standard spelling in British English, ...

 Snuck and sneaked are both correct past tense forms of sneak. Snuck is more common in American English, while sneaked ...

 Cancelled and canceled are both correct spellings. Canceled is the preferred spelling in American English, while cancelled is the standard ...