根据内容及首字母提示完成短文。

    There are four seasons in the year. Then I will i____ the four seasons of the year.

    In the year, the f____ season is spring. Spring is a beautiful season.

    Summer comes a____ spring. It's the h____in a year. In summer there are some persons at home and t____ on the air-conditioner(空调). Summer is hot and sunny. But I like summer very much. Because I can eat some ice-creams and go s____.

    I think autumn is better than summer. Autumn is a wonderful season and a h____ season. In autumn I can eat so many fruit and food. And the trees are golden.

    Winter is the l____ season of the year. In winter I can play s____ with my friends.

    In my city, every season has three m____. The weather of the season is different from that of any other.

能否从等式（2a﹣1）x=3a+5中得到x=$\frac{3a+5}{2a-1}$，为什么？反过来，能否从x=$\frac{3a+5}{2a-1}$中得到（2a﹣1）x=3a+5，为什么？

我国山区包括山地、丘陵和崎岖的高原，下面有关山区的叙述正确的是（    ）