One could carry this television by oneself.

这台电视可以己搬。

And now for " by oneself." " By" is a preposition.

现讲by oneself。by是介词。

One doesn't do it by oneself.

一个人不能独做这件事。

In such a case, studying by oneself is crucial to improve your learning efficiency.

这种情况下, 于提高你的习效率至关重要。

It is lonely living by oneself.

一个人住很孤独。

America is a nation known for the idea of making things by oneself.

5. 美国是一个以己制造东西的理念而闻名的国家。

" Alone" , instead of saying " alone" , you could say: " by oneself" , " on one's own" , " by themselves" .

“独”，替代这个词，你可以说：“一个人”，“己”，“他们己”。