①～⑩是几种有机物的名称、分子式或结构简式：

①C₂H₂②新戊烷   ③苯   ④ ⑤

⑥CH₃CH（C₂H₅）CH₂CH（C₂H₅）CH₃⑦C₅H₁₀⑧ClCH=CHCl     ⑨C₅H₄

⑩

据此回答下列问题：

根据短文内容，回答下列问题。

    It's December. It's snowy and the weather is really cold in the north of China. You can see many children playing with snow（雪）. Some of them are making snowmen. Some are skating on the river, because it's so cold that the water in the river freezes(结冰). It's a white world. How beautiful! But in Australia now, the weather（天气）is hot. Many people go swimming in the sea. (大海) They are having a good time. Jim and his friends are playing soccer near the sea. The sunny weather is really cool to them. They want to swim after playing soccer.

    Why are they swimming in December? It is winter, isn't it? Yes, it is in China. But it isn't in Australia. That's because we, Chinese and Australians, have different seasons(季节) in a year.

1949年，***致信宋庆龄：“新的政治协商会议将在华北召开，中国人民革命历尽艰辛，中山先生遗志迄今始告实现。”信中所说的这次会议通过并被中央人民政府接受其成为新政府的施政方针的重要文献是（   ）