UNCF=United Nations Children's Fund 联合国儿童基金
UNabbr.(=United Nations) 联合国pron.<口>人,事物,家伙,东西
undaped vibration无阻尼振动
unbalanced gamete不平衡配子
unerring instinct正确无误的直觉
unregistered land未登记的土地
unbalanced masses不均衡质量
unresolved doubts[法] 未解决的疑团
unclassed felling无节制采伐
"sit straight"
"stood defiantly with unbowed back"