题干
---Jack didn’t pass the examination last week.
---_______? He had been working so hard at his lessons.
---_______? He had been working so hard at his lessons.
A：What for
B：Pardo
C：Did he
D：How come
答案(点此获取答案解析）
D
中涂色，要求同一区域涂 同一颜色，相邻区域涂不同颜色（
与
、
与
不相邻），现有4种颜色可供选择，则不同的涂色方案有 ( )
