He saw the MP4 player a moment ago, but he didn’t know how it disappeared .
A. gradually
B. foolishly
C. briefly
D. magically
网友回答
A. gradually
B. foolishly
C. briefly
(答案→)D. magically
解析：副词gradually逐渐地；foolishly愚蠢地；briefly简洁地；magicallyadv.如魔法般地，用魔法地；句义：刚才他还看见这个MP4，但是他不知道它怎么像魔法般地就消失了！根据句义说明D项正确。