独自一人

I work more efficiently on my own.

我人工作效率更高。

He went to the bandits' lair all by himself!

人闯了土匪窝。

I was alone with no money or possessions.

我人，没有钱，也没有财产。

He was alone in the house.

人在家里。

He was alone in the room.

人在屋里。

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

虽然人生活很少会有乐趣，但还是可以习。

He was unhappy when alone.

人时感到不快活。