Plain of厄斯垂伊伦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-colored Sunbirdn.纯色直嘴太阳鸟plain-folks technique平易近人法Plain and Cipher Switch明密开关plain bar reinforcement无节钢筋plain of marine erosion海蚀平原plain pick-up transfer普通传递装置plain carbon steel plate普碳钢中厚板plain combustion chamber普通燃烧室plain spring stethoscope扁弹簧式听诊器plain position indicator平面位置显示器