注意力集中性方面的障碍包括（）
A．注意增强
B． 注意固定
C．注意缓慢
D． 注意狭窄
E．注意减退
参考答案：C,D
The problem is hard but Tom has _____ a good idea to solve it.[ ]
A. caught up
B. come up with
C. caught up with
D. came up with
