1 used when the person who does an action is also affected by it (表示某人受自己行为影响)某人自己:
One can teach oneself to play the piano but it is easier to have lessons.弹钢琴是可以自学的,但有人教,学习起来就比较容易。
2 used to emphasize sth (用于强调):
One could easily arrange it all oneself.谁都可以自己安排好。
(all) by oneself
1 alone 独自
☞Look at the note at alone. 参看alone的注释。