set out 与 set off 有区别吗？

set out和set off都有出发的意思，区别是：set off更含开始(旅行、赛跑等）的意思，例：What time are you planning to set off tommorrow?
你明天打算几点钟启程？
They've set off on a journey round the world.
他们已经开始环游世界。

set out意思是从某地出发上路 例：She set out at dawn.她天一亮就动身了。

一般的，set out还有陈述说明的意思，set off还有使爆炸的意思。

set out与 set off同义, 都作 "出发、动身" 解。后面跟介词for短语, 也可接不定式, 表示 "动身去某地" 。例如:

The next day Holmes set off/out for the place where the lady lived.

They set out/off to look for the lost child.

表示 "打算、准备 (做某事) " , 后面常接不定式。例如:

He set out/off to break the world record.

自己理解