by oneself与on oneself的区别

没有on oneself 的这个短语， 应该是by oneself 和for oneself 的区别:

by oneself: 单独, 独自; 单独，独自; 单独，靠自己; 单独；独自,自行

One is firmly established by oneself .

for oneself: 独自, 独力地; 独自地; 为自己; 自己亲自干……

One cannot do such a thing for oneself .