Translation:We drink a juice and you eat the rice.
One time I was eating lunch with co-workers from China, and I was doing my best to eat with chopsticks. I do know how to handle chopsticks, but clearly not like a native. They challenged me on my chopstick usage, and I proved it by picking up a single grain of rice and eating it.
So -- it's possible to eat "ONE RICE" .. but really, if you think about it, Rice is served as hundreds of grains of rice in a dish, and therefore it is one of those words that is always plural - like sand.