区别1
两者均表示“独自”、“单独”,有时可互换。如:
He likes living alone (或by himself). 他喜欢独居。
区别2
两者均不可用very 修饰,但可用all 修饰。如;
Can you finish the work all alone? 你一个人能完成这工作吗?
He went to see the film all by himself. 他独自一人去看了电影。
区别3
在表示人数方面,alone (侧重指没有外人)不如by oneself(指绝对一人)那样绝对。如:
误:I want to be by myself with Mary.
正:I want to be alone with Mary. 我想单独与玛丽在一起。
区别4
alone 还可放在名词或代词之后,表示“仅仅”、“只有”(与only 同义,但only 放在名词或代词之前),by oneself 不能这样用。如:
He alone can do it . ( = Only he can do it. ) 只有他才做得了。