A 12-year-old boy got lost on the subway after going out alone on Sunday. The boy came to Shanghai to visit his parents during the summer holiday. Although his parents were happy to see him, they ____ little time with him. The boy did his homework for two ____ and felt bored, so he went out to play on the subway. He had fun playing there. But when he felt tired and hungry, and wanted to go home, he didn't know at which station he should get off. The police found the boy ____ on the subway and took him to the office. They bought him something to eat and asked him some questions. The boy's parents couldn't find him after arriving home. They felt ____ and called the police right away. They got to the police office and saw ____ son. They were very happy and thanked the police.

为参加2012年“河源市初中毕业生升学体育考试”，小峰同学进行了刻苦训练，在投掷实心球时，测得5次投掷的成绩(单位：m)为：8、8.5、9、8.5、9.2．这组数据的众数和中位数依次是(      )

如图所示，两个质量分别为m₁=2kg  m₂=3kg的物体置于光滑的水平面上，中间用轻质弹簧秤连接。两个大小分别为F₁=30N  F₂=20N的水平拉力分别作用在m₁  m₂上，则（      ）