plain to对 ... 是清楚的
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 fuse cut-out敞露式熔丝保险器
plain grinding wheel普通砂轮
plain clothes police便衣警察
Plain pygmy squirreln.平原矮松鼠
plain mug with cover素色盖杯
plain shaking screen平面摆动筛
plain traction table平面牵引床
plain reducing cross不带边异径四通
plain-sawed lumber弦切板
Plain mountain Finchn.林岭雀