1949年10月1日，中华人民共和国中央人民____成立，在首都北京举行了____。

现有由同种材料制成的A、B两金属球，其中一个是实心的，它们的质量分别为128g、60g，体积分别为16cm³、12cm³．
（1）通过计算说明，哪一个球是实心的？
（2）这种金属材料的密度是多少？
（3）空心球的空心部分体积是多大？

    Liu Tao's grandparents live on the1. They have a big house2 the house, there is a park.

    Today is 3Liu Tao and his parents don't study or 4

Now they are at Liu Tao's grandparents' house. All of them are5 lunch around the table. There are some rice dumplings on the table. Liu Tao likes6 the rice dumplings with meat and eggs. But his parents like the7 with jujube (枣子). Grandpa is telling a 8 about Quyuan.

    They are all listening to him. They are going to watch a dragon boat race in the park in the 9It will be very exciting (令人激动的). Liu Tao likes the races. He can't10 to see.