Countable Noun:
* When referring to individual grains of rice, you use it as a countable noun. For example:
* "There were a few grains of rice stuck to the plate."
* "I found a rice on the floor." (Less common, but still grammatically correct)
Mass Noun:
* When referring to rice as a general substance or food, you use it as a mass noun. For example:
* "I like to eat rice with curry."
* "Can you pass me the rice?"
* "There's not much rice left."
The distinction lies in whether you are focusing on individual grains or the substance as a whole.