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....
这种椅子具有可调节的优点.The chair has the virtue of being adjustable.琴弦之间互相调节的失真已经基本上被消除了.The intermodulation distortion between the strings is virtually eliminated.你眼睛的瞳孔是自动调节的.Your eye pupil adjusts automatically....