question: bamboo slips:books
choices.label: A B C D
choices.text: clarinet:pan flute hourglass:clock writing brush:electric pen violin:drum
explanation: the ancient form of "books" is "bamboo slips". the "clarinet" and "pan flute" are both types of musical instruments. the expression for "clock" in ancient times was "hourglass". there is no obvious logical relationship between "writing brush" and "electric pen". the "violin" and "drum" are both types of musical instruments.
relation: clarinet pan flute R2.4
relation: violin drum R2.4