英文:一个人 的写法?

应该用a person

偏向动作独自完成
1 sb .......alone.
2 ab.....on one's own.
3 ab......by oneself.

指有一个人.....
1 A person .....
2 A man.....

一个人:a person...
如果你想问的是"一个人做XXX"的一个人就是
on one's own,by oneself

alone 或者only by oneself(可以根据具体情况换成himself herself .....)或者one person 或者a man 不过我觉得还是alone比较好，不会像其他的感觉很生硬，一看就是"Chinglish"

by oneself;alone;do it yourself(DIY);
one;a/one person

one person