question: kitchen knife:cutting board
choices.label: A B C D
choices.text: train:railway aircraft:engine computer:operating system planet:orbit
explanation: "kitchen knife" and "cutting board" belong to the corresponding relationship of matching use. "train" and "railway" belong to the corresponding relationship of matching use. "engine" is an integral part of "aircraft", and "engine" and "aircraft" are not used together. the "operating system" is an integral part of "computer", and "operating system" and "computer" are not used together. "orbit" is the motion trajectory of a "planet", and "orbit" and "planet" are not used together.
relation: engine aircraft R2.3
relation: operating system computer R2.3
relation: orbit planet R3.10