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 river networks平原河网
plain miller machine平面铣床
plain-carbon steel碳素钢
plain coloured towel素色毛巾
plain capillary tube扁平(形)毛细管
plain artificial fur素色人造毛皮
Plain Indian Culture大草原印第安人文化
plain antenna system简易天线设备
Plain-backed Pipitn.纯背鹨
plain calliper gauge普通卡规