set off 出发，使工作，使爆炸，让闹钟响起

　　We're going to have to set it off manually. 我们得手动启动它了。

　　They set off to get the baby back. 他们接孩子去了。

　　We set off to visit the country. 我们出发去乡下探亲。

　　We set off on a short trip to Tokyo. 我们启程前往东京做短途旅行。

　　Where has your son gone? 你儿子去哪了？

　　He set off to travel around Europe. 他去周游欧洲了。