独自一人用英语有以下两种说法：
1、by oneself，比如"我独自一人"就是by myself。
2、on one's own，比如"我独自一人"就是on my own。
拓展资料
by oneself
1、One is firmly established by oneself.
卓然自立。
2、The infirmity that felling is so by oneself with need to be depended on!
感觉自己是那么的虚弱和需要依靠！
3、It's more satisfying to do the job by oneself.
独自一人做这项工作更让人感到满足。
4、I really hope that can know the languages of all countries by oneself.
我真希望自己能懂所有国家的语言。
5、Visitors can drive by oneself and have.
游人可自驾车而上。
on one's own
1、Success in study mainly depends on one's own efforts.
学习主要靠自己努力。
2、Don't be silly, you must depend on one's own.
别太傻了，你要靠自己。
3、Most of the shadows of this life are caused by standing on one's own sunshine.
我们一生中大多数的阴影是因我们自己的阳光所造成的。
4、Reflect on one's own thoughts and feelings.
深刻地反思自己的思想和感觉。
5、Because be away on official business, the exercise of my ability to adapt is strong, and have good stand on one's own ability and communication ability.
因为出差，锻炼了我的适应能力比较强，并且有很好的独立自主能力和沟通能力。