No one knows the reason that they choose to leave, they didn't leave a word slice speech. But I know, they are all standing alone kids.

没有人知道她们选择离开的原因，她们没有留下只字片言。但我知道，她们都是孤独的孩子。

youdao

A step size of -1 goes through the word backwards, so the slice [: : -1] generates a reversed string.

步长如果为- 1，意思就是倒序读取字符串，所以[：- 1]这个切片就会生成一个逆序的字符串了。

youdao