set off,set about,set out 的用法和区别?

set off,set about,set out 的用法和区别?

（1）set off出发；【set off for a place出发到某地】【set off from...to..从...出发到】动身；使爆炸,引起；
（2）set about一般意为开始（做某事）set about doing sth=set out to do sth(开始,着手于做某事)
（3）set out出发,动身,着手 安排