ON是开的意思，OFF是关的意思。
onprep.(覆盖、附着)在…上(意指接触物体表面；adv.表示持续性
He is well on his way to show business immortality.
他很快就会成为娱乐界永世流芳的人物。
The country has a poor record on human rights.
这个国家人权记录不佳。
She recommended that I should take some time off.
她建议我应该休息一段时间。
水利万物而不争,
而万物莫能与之争。
