question: united:cooperation
choices.label: A B C D
choices.text: indifferent:aloof study:hard colleague:friend satisfaction:happiness
explanation: "united" and "cooperation" have similar meanings. "aloof" and "indifferent" have similar meanings. "hard" can modify "study", but the two meanings are not similar. a "colleague" can be a "friend", and a "friend" can also be a "colleague". there is no obvious logical relationship between "satisfaction" and "happiness".
relation: united cooperation R1.1
relation: indifferent aloof R1.1
relation: hard study R4.3
relation: colleague friend R2.7