that's called free rider.


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送交者: bullrider 于 2010-09-06, 13:18:19:

回答: 读了卫生部的问答手册,关键地方(第二部分)还是没明白。 由 Amsel 于 2010-09-06, 12:00:30:

Free riding is good for individuals. But if there are too many free riders, the system fails.



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