achievement
n
1 [U] action of achieving 完成; 达到
celebrate the achievement of one's aims 庆祝愿望的实现.
2 [C] thing done successfully, esp with effort and skill 成就, 成绩（尤指藉努力和技巧而得到者）
the greatest scientific achievement of the decade 这十年的最伟大的科学成就. =>Usage at act1 用法见act1.