threeling三连晶threenum.三n.三；三个adj.三个的Three-way Straight Pipe三通直管three stable state device三稳态设备Three plus two is five.三加二得五。three core volute chamber三心大涡壳three-tier clientserver三层客户服务系统three thousand and eleven(=3011) 三千零十一three - dimension graph三维图形three - wheeled vehicle三轮汽车Three points bending test三点弯曲试验three-knob x-ray nuit三钮X线装置

1. Environmental awareness was non-existent three decades ago.
   环保意识在三十年前是不存在的。
2. What China has done in less than three decades is nothing short of astonishing.
   中国在短短三十年里所做的从来不乏令人惊异之举。