0 If a light or a machine goes off, it stops working. -- (電燈)熄滅;(機器)停止運行,停止運轉
1 If a bomb goes off, it explodes. -- 爆炸
His gun went off accidentally. 他的槍不小心走火了。
2 If food or drink goes off, it is not good to eat or drink any more because it is too old. -- (食物、飲料等)變質,變壞,腐敗
3 If a warning device goes off, it starts to ring loudly or make a loud noise. -- (警報器等)突然發出巨響
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路,一步步也能走完,再短的路,不迈开双脚也无法到达。