单独的副词是什么

　　I tried to picture what it would be like to live alone.

　　我努力设想一个人单独生活是什么情景。

　　I started to feel afraid of going out alone at night.

　　我开始害怕夜间单独外出了。

　　I left them alone, as I felt I was in the way.

　　我留下他们单独在一起，因为我觉得我碍他们的事。

　　Don't go out alone after dark.

　　天黑后不要单独外出。

　　I don't feel easy about letting the kids go out alone.

　　让这些孩子单独出去我不放心。