three R rs读、写、算三种技能threenum.三n.三；三个adj.三个的three thousand five hundred and sixty(=3560) 三千五百六十three-level space vector modulation三电平空间矢量调制three thousand one hundred and twelve(=3112) 三千一百一十二three -point boundary value problem三点边值问题three--five-year-old children3-5岁幼儿three thousand eight hundred and five(=3805) 三千八百零五three-dimensional discrete elements三维离散元three-dimensional calculation model三维计算模型three-dimensional projection screen立体投影屏three-dimension wind velocity field三维风场