běi jīng shén me jì jiē zuì měi 
问：北京什么季节最美？
Q：What is the most beautiful season in Beijing?

        qiū tiān zuì měi
答：秋天最美。
A：Autumn is the most beautiful.

[chūn tiān] 春天 (spring)
[xià tiān] 夏天 (summer)
[qiū tiān] 秋天 (autumn)
[dōng tiān] 冬天 (winter)