three plyadj.三层的(三股的；三夹板)threenum.三n.三；三个adj.三个的Three Gorges culture三峡文化three-fluted drill三槽钻头three-eighths rule八分之三法则three-lipped drill三缘钻头three phase diagrams三相图three-wire leveler三丝水准测量three-body problem三体问题three points hanging三点吊挂three-state enable三态使能,三态启动three-quarter shot双人近景