【题目】Traditionally, college students hold a graduation ceremony to encourage themselves when they are to _________ on their life journey.
A.set up
B.set off
C.set about
D.set down

【答案】B
【解析】句意：从传统意义上说，大学生举行毕业典礼是为了在开启他们人生旅程之前鼓励他们自己。set off”引爆，动身，启程“，故选B