Reportedly yesterday a group of American soldiers were walking along the road in Iraq wh

问题补充：

Reportedly, yesterday a group of American soldiers were walking along the road in Iraq when a bomb was , three of whom were killed．

A. set off

B. set out

C. set up

D. set about

答案：

(答案→)A. set off

B. set out

C. set up

D. set about

解析：考查词组;A. set off引发，引爆，出发，B. set out开始，动身，C. set up建立，D. set about出发，句意是：据报道，昨天一群美国士兵沿着伊拉克的公路走，这时炸弹爆发了，有三人丧生。选A。