VOA慢速英语:研究人员:是什么促使人们合作的?

random - adj. chosen without a particular plan or pattern

defector - n. a good or helpful result or effect

benefit - v. one who causes a weakness or failure

generous - adj. showing kindness and concern for others

step up - v. to do better, make a greater effort, or improve your performance

hypocrite - n. a person who claims or pretends to have certain beliefs about what is right but who behaves in a way that disagrees with those beliefs

status - n. the position or rank of someone or something when compared to others in a society