1．unnecessary [?n?nes?s?ri] adj. 不必要的；多余的
2．reward [r??w?:d] n. 回报
3．weigh the risk and the reward 权衡风险和回报
4．sth. seems worth doing 似乎值得做某事
5．reference [?refr?ns] n. 参考
6．the same reference standard 相同的参考标准
7．scare [ske?(r)] vt. 惊吓；使害怕
8．expert [?eksp?:t] n. 专家
9．take risks 冒险
10．risk-taker [r?sk'te?k?(r)] n. 冒险者
11．hunt [h?nt] vi. 打猎
