The president's envoy set off on another diplomatic trip.

总统特使再次踏上外交之旅。

《柯林斯英汉双解大词典》

I set off on this trip with the vague expectation that three months of navel-gazing would clear my head of the frustration, that is for me at least, the constant shadow of middle age.

我出发旅行时，有一种模糊的期盼：三个月的内心自省会驱走我心里的失落感，对我来说，至少是那挥之不去的中年阴影。

youdao

So the week after Easter we set off by bike on a four-day trip to Wimpfen, Amorbach, and Miltenberg.

因此复活节后那个星期我们骑自行车出发去温普芬，阿莫·巴赫和米尔藤贝格进行为期四天的旅行。

youdao

The team of students and research volunteers set off on a three-week boat trip to examine the area.

VOA: special.2009.09.22