Do be careful with those fireworks; the slightest spark could them .A. set; outB. set; o

问题补充：

Do be careful with those fireworks; the slightest spark could them .

A. set; out

B. set; off

C. set; about

D. set; up

答案：

A. set; out

(答案→)B. set; off

C. set; about

D. set; up

解析：

试题分析:考查短语辨析。set out 出发；set off 引爆，引发；set about 着手做；set up 建立，成立。根据句中的fireworks、the slightest spark可知此处指“引燃，引爆”的意思，所以填B。句意：这些烟火要格外小心, 稍有火星就能引起爆炸。