1、我认为秋天是一年中最美的季节。

i think autumn is the most beautiful season in a year.

2、秋天时叶子变黄。

the leave turn yellow in autumn.

3、在秋天的晚上，我感到一丝凉意。

i feel a little cool in the autumnal night.

4、秋天里树木都是光秃秃的。

the tree were naked during autumn.