问题补充:
---What on earth are the police busy with?
---They have been looking into how the plane crash .
A. came out
B. came up
C. came down
D. came about
答案:
A. came out
B. came up
C. came down
(答案→)D. came about
解析:词义辨析。came out出现,出版,结果是came up;提出来(流行,走近,来临,上,升);came down下来,下落; came about发生。他们一直在调查坠机事件是怎么发生的?选D。