oneself与by oneself的区别

Question

例句：
after two years,my father told me and my brother that he felt we were old enough to cut the grass by ourselves.
after two years,my father told me and my brother that he felt we were old enough to cut the grass ourselves.
答案上只有第一句
第二句不对

Answer 1

oneself 是某人自己
by oneself 是由某人自己

你的列句第一句：2年后，爸爸告诉我和哥哥他觉得我们足够年龄可以自己修剪草坪了

第二句其实也差不多，也是翻译成我们自己修剪草坪

英语翻译不要死板，主要根据内容来的

Answer 2

他们是一样的，前都更强调这项工作是自己独立完成。

Answer 3

我们老师说的和楼上差不多
你可以认为BY可省略

Answer 4

oneself某人自己
by oneself=on one's own =alone 靠某人自己
两个在这个句子中用法差不多，没什么大的区别

Answer 5

oneself指某人自己， by oneself指靠某人自己，相当于without help

Answer 6

oneself ...自己
by oneself 靠。。。自己