问题补充:
The computer system suddenly while he was surfing the Internet.
A. broke up
B. broke out
C. broke in
D. broke down
答案:
A. broke up
B. broke out
C. broke in
(答案→)D. broke down
解析:短语辨析。A关系破裂;分解;B爆发;C闯入;D机器坏了,身体垮了;分解;抛锚;崩溃;结合句意可知D正确。句意:当他在上网的时候,计算机系统突然就崩溃了。