by oneself
表示独自或没有帮助。
One should learn to do it by oneself.
一个人应该学会独自做这件事。
亲自
The reflexive form of the indefinite pronoun 'one', used when the subject and the object are the same person.
自己；亲自
pron. A reflexive form of the indefinite pronoun one.；Commonly writen as two words, one's self.
One should always be honest with oneself, even when no one is watching.
一个人即使无人旁观，也应该对自己诚实。
用法提示：oneself 在此作介词 with 的宾语，泛指任何人自己，是反身代词的用法。
It isn't easy to take care of oneself when you work long hours.
工作时间很长时，照顾好自己并不容易。
用法提示：oneself 在此作不定式 to take care of 的宾语，泛指一般人自己。
Learning to laugh at oneself makes life a lot easier.
学会拿自己开玩笑会让生活轻松很多。
用法提示：oneself 在此作介词 at 的宾语，泛指任何人自己。
表示独自或没有帮助。
One should learn to do it by oneself.
一个人应该学会独自做这件事。
表示亲自或独立地。
One must see for oneself to believe it.
必须亲眼所见才会相信。
表示保密或不与人分享。
One often keeps one's feelings to oneself.
人们常常把感受藏在心里。
反身代词作宾语，与主语一致。
One can teach oneself many skills.
人可以自学许多技能。
oneself 是正式、书面且与 one 呼应的反身代词；口语中通常把 one 一并改为 you，再用 yourself 表达泛指。若主语仍为 one 而只用 yourself，会造成人称不一致。
grammar · medium
易错句子One should respect himself.
正确表达One should respect oneself.
当主语是泛指代词one时，反身代词必须用oneself，不能用himself或yourself。
grammar · medium
易错句子One can finish the task by himself.
正确表达One can finish the task by oneself.
在固定搭配by oneself（独自）中，反身代词应与主语一致，主语为one时应用oneself。
与“oneself”（自己，亲自）相对，指代另一人，不能用作反身代词。
与“oneself”（自己）相对的复数代词，指其他人，不能用于反身意义。
oneself用于泛指任何人，myself特指说话者本人
oneself用于泛指，yourself特指听者本人
自学
She taught herself to play the guitar.
她自学了弹吉他。
独自；单独
He prefers to study by himself.
他更喜欢自己学习。
为自己；亲自
You need to see it for yourself to believe it.
你得亲眼看到才能相信。
玩得开心
We enjoyed ourselves at the party.
我们在聚会上玩得很开心。
伤害自己
Be careful not to hurt yourself with that knife.
小心别用那把刀伤到自己。
不与人交往；保持独处
He tends to keep to himself at work.
他上班时总是不与人交往。
与oneself相关，指对自身的思考和分析。
涉及对自身价值的评价，与oneself紧密关联。
探索和理解自己的过程，核心是自身。
主动照顾自己的身心健康，围绕自身展开。
对自己行为的管理和控制，直接关联自身。
独自；靠自己
She traveled to Japan by herself.
她独自去了日本。
做自己；自然舒适
Just relax and be yourself at the interview.
面试时放松做你自己就好。
不与人交往；独来独往
He keeps himself to himself and rarely talks to neighbors.
他独来独往，很少和邻居说话。
认识自己是智慧的开始。
Many motivational speakers quote Aristotle's saying: 'To know oneself is the beginning of wisdom.'
许多励志演讲者引用亚里士多德的话：'认识自己是智慧的开始。'
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.