OUT 的語氣比較粗魯

OFF 的語氣比較平和，普通人都這么說

set off: 出發(fā),側(cè)重于去某個地方

例句與用法:

If you want to catch that train we'd better set off for the station immediately.

你要是想趕上那班火車，咱們就最好馬上動身去火車站。

They've set off on a journey round the world.

他們已經(jīng)開始環(huán)游世界.

set out:

出發(fā)，開始，側(cè)重于開始做某事，還有規(guī)劃，展現(xiàn)的意思

例句與用法:

They succeeded in what they set out to do.

他們打算做的事已經(jīng)做成了.

set about:

開始,著手，與set out意思相近，但set out后加不定式，即set out to do sth,而set about后加 ing形式，即set about doing sth.

例句與用法:

1. You must set about your work at once.

你必須立即開始工作。

2. Do you know how to set about going on this work?

你知道怎樣著手進(jìn)行這項(xiàng)工作嗎？。