独自一人

He went to the bandits' lair all by himself!

自一人闯了土匪窝。

I work more efficiently on my own.

我自一人工作效率更高。

I was alone with no money or possessions.

我自一人，没有钱，也没有。

He was alone in the house.

自一人在家里。

He was alone in the room.

自一人在屋里。

One can habituate oneself to living alone, though rarely with any pleasure.

自一人生活很少会有乐趣，但还是可以习惯的。

He was unhappy when alone.

自一人时感到不快活。