three Ps三Pthreenum.三n.三；三个adj.三个的three-plug method三弧法three-roller mill三辊中速磨three phases method三阶段法three chains tunnel三车道连拱隧道Three River Sources三江源three-level atoms三能级原子threebing machinery脱粒机具three-input adder全加器,三输入端加法器,三输入加法器three days' journey三天的旅行three-point assay三点检验