--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：考查短语辨析。e out 开花，出版，e up 走近，上来，被提出，e down 降低，下来，e about 产生，发生.答语的意思为：他们在一直调查飞机坠毁是怎么发生的。所以答案选D 。