high-flyers who are forced to work in teams may be undervalued and free-riders empowered.

2017年6月四级真题（第三套）阅读 Section B

Developed nations such as Australia, the United States, Canada, and European countries are essentially climate "free-riders": causing the majority of the problems through high greenhouse gas emissions, while incurring few of the costs such as climate chan

2016年12月六级真题（第二套）阅读 Section C