I'm alone at home.

我独自一人在家。

youdao

The only time I can think clearly is when I'm alone.

我能清醒思考的惟一时间就是当我独处时。

《柯林斯英汉双解大词典》

There's crowded but I'm alone.

这里众人广坐，我却孤身一个。

youdao

I'm coming to get you. Then you and Iare gonna go somewhere alone.

VOA: standard.other

What I've learned which I appreciate so much is just to be reminded that I'm not alone, even I felt alone a lot of the times.

我所学到的让我珍视的,是提醒自己并不孤单，即便很多时候我感到孤独。

普林斯顿公开课 - 人性课程节选

To figure out even what this thing is, let alone how to use it properly. So, you know, I'm sympathetic.

就连认出这是什么东西（都很困难），更别说正确应用它了，所以我很同情这点。

经常犯的失误 - SpeakingMax英语口语达人

Try, for instance, to spot the artistic difference in the posters, right, for Hollywood's Mr. Jones, starring Richard Gere, and Bolly-wood's Akele Hum Akele Tum (I'm Alone, You're Alone).

CNN: Borrowed by Bollywood

And I'm never happier than when I'm alone.

FORBES: Dear Abby

I've articulated the pleasure of birding, in much the same way, and if only to myself, when I'm alone in the woods and trying to dissect my ability to spend hours with my binoculars focused on something 6 inches long a thousand feet away, my glasses fogging over, and my neck and arms aching.

WSJ: Park Filmmakers Wing It