出典:Wiktionary
It is difficult for me to try it alone.
Please come in one by one.
I'll be okay by myself.
That would be sufficient.
I'm worried about being alone.
I don't want to do that alone.
It is in your discretion as to how you dispose of it.
I have to go alone.
I don't want to do that alone.
That won't get anywhere with just one person.