---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
网友回答
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。