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