question: water:ice
choices.label: A B C D
choices.text: rice:cooked rice iron:rust cloud:rain tree:wood
explanation: "water" and "ice" are two different physical forms. the raw material of "cooked rice" is "rice". the oxidation compound of "iron" is "rust", and the two do not have the same nature. "cloud" and "rain" are two different physical forms. "Tree" includes "wood", but "tree" has life and "wood" has no life. The two do not have the same essence.