We'll have a (quick) nosh, then (start out). 我们先吃些快餐再出门儿. If you want to catch that train we'd better (set off for) the station immediately. 你要是想赶上那班火车,咱们就最好马上动身去火车站. He will (leave for) Shanghai tomorrow. 明天他将出发去上海. 由上可见,在指“出发”而言,"start out ,leave ,set off" 意思和用法是一样的,如果后面要加地点则加上 "for"
