铅是早在古代就已知的金属之一。Lead was one of the metals known to the ancient world.水银是一种已知的有毒物质。Mercury is a known poison.人们通常从已知的事实中推断未知的事实.People usually infer an unknown fact from a known fact....
Objective : To study tissue chara ct eristics of Humulus lupulus, powder characteristics, physical and chemical characteristics.目的: 探讨忽布的组织构造 、 粉末特征及常见的理化特性....
一位被警察拦下的摩洛哥青年拒绝出示他的证件。A young Moroccan stopped by police refused to show his papers.这么多年来，头一回有人要我出示身份证。For the first time in many years, I got carded.史蒂夫·维克斯因对亨特犯规被出示黄牌。Steve Vickers was yellow-carded for a foul on Hunt....