plainlyadv.清晰地；明显地；直截了当地；朴素地plainadj.清楚的；简单的；坦白的；平常的；朴素的；纯的n.平原；广阔的区域adv.完全地；纯粹地plain soup plate素色汤盘plain rib fabric平色罗纹针织物plain rubber tip无孔橡皮头plain stuBBorn.十分倔强plain fissure bur裂隙平切(牙)钻头plain and natural平易自然plain coordinates明码坐标plain spark-gap普通放电器plain clothes man便衣警察plain of abrasion海蚀平原