The computer system suddenly while Paul was searching for information on the Internet.A. b

问题补充：

The computer system suddenly while Paul was searching for information on the Internet.

A. broke in

B. broke out

C. broke up

D. broke down

答案：

A. broke in

B. broke out

C. broke up

(答案→)D. broke down

解析：考查动词短语辨析。句意：Paul正在上网搜索信息时，电脑突然出毛病了。A闯入，打断；B爆发；C分裂，解散，放假；D出毛病，损坏，失灵，分解，失控。故选D。