先導的英文：
a guide; a forerunner; a precursor; a vanguard; a pacemaker; a mentor
v. 引导；引路；带领；操纵；影响；指导
n. 向导；导游；指导者；指导原则；准则；指南；入门书
To be guided by destiny
听天由命
Reason be the guide and light of life .
理性是人生的灯塔。
control lever guide collar
操纵杆导套
n. 先驱；预兆
Each pretends to be the counterpart of the forerunner.
每一个都自命是和前面一个相匹敌的。
These faculae frequently are the forerunners of sunspot formation
这些光斑常常是形成太阳黑子的先兆。
The alchemists were the forerunners of the scientists of today
炼金术士是今日科学家的先驱。
n. 先驱，前导，先锋；预兆；前身
It was the precursor of or to the modem jet plane.
它是现代喷汽飞机的前身。
These include the chlorophyll precursor protochlorophyllide a
这些受体包括叶绿素的前体原叶绿酸a。
Crazing is the invariable precursor of brittle fracture.
出现小裂纹必然是脆性断裂的前兆。