正方体的棱长为a，由它的互不相邻的四个顶点连线所构成的四面体的体积是（    ）

最高法院在今年全国人民代表大会的工作报告中指出，“严格实行非法证据排除规则，健全死刑复核法律援助制度，完善司法救助制度，进一步加强人权司法保障。”这表明（  ）

①坚持司法独立是依法治国的重要保证②人民当家作主的权利有真实性的特点③最高人民法院须接受全国人大的领导④推进法治中国的建设需要制度的完善

    I like school days. I can learn many things from school. We have four classes in the morning and two in the afternoon. I like weekends, too. We don't go to school on Saturdays and Sundays. I often play ping-pong and play basketball on Saturday morning. I often play the violin (小提琴) on Saturday afternoon. I often do homework and play football on Sunday morning. I often go to the park on Sunday afternoon.

百团大战的主要作战目标是（    ）