question: oxygen:combustion
choices.label: A B C D
choices.text: eat:healthy thunder:rain water rise:floating boat league member:party member
explanation: "oxygen" is a necessary condition for "combustion" "eating" is a necessary condition for "health" "thunder" is not a necessary condition for "rain" the reason for the "boat floating" may be "the rising water" "league member" and "party member" are both political identities
relation: oxygen combustion R5.4
relation: eat healthy R5.4
relation: water rise floating boat R5.1
relation: league member party member R2.4