Sunday 1 the favorite day for our family. My parents 2  not 3 work. My sister and I 4 go to school. We 5 at home and 6 in the morning. In the afternoon, my sister and I 7 out to buy some different things. My sister likes songs. She 8 new tapes. I buy story books, a frisky, a kite and things 9 that. We also buy some small gifts (礼物) for our parents. We 10 them. They love us very much. We live in a happy family.

古人称黄河水是“一石水，六斗泥”．创意中学综合实践小组从黄河中取了2×10^﹣3m³的水，称得质量为2.2kg，由此可知含泥沙的黄河水的密度为____kg/m³．一条货船在黄河中航行时，浸在水中的体积是30m³．船受到的浮力为____N．在码头将货物卸下后，河水对船底压强大小的变化情况是____（本题g取10 N/kg）．