阅读下面短文，并用英语回答问题(请注意每小题后面的词数要求)。

    It's December. It is snowy and the weather is really cold in the north of China. You can see many children playing with snow. Some of them are making snowmen. Some are skating on the river. It's so cold that the water in the river freezes (冻结). It's a white world. How beautiful!

    But in Australia, the weather is hot now. Many people go swimming in the sea. They are having a good time. Jim and his friends are playing soccer near the sea. They want to swim after playing soccer.

    Why can they swim in December? It is winter, isn't it? Yes, it is in China. But it isn't in Australia. That's because China and Australia have different seasons in a year.