unbagvt.把 ... 从袋里倒(或取、放)出来UNabbr.(=United Nations) 联合国pron.<口>人，事物，家伙，东西undulating tube model波纹管模型undeveloped territory未开发地区unfertilized histosol未施肥的有机土unknotted sphere pair不打结球对uncracked hydrocarbon未裂化的烃undisclosed principal未公开的委托人unemployment pressure失业压力uncoiling of molecule分子伸直uncontrolled variable不可控变量,不可控制变数unpalatable truths.令人不快的事实