lonely:

A person can be alone without feeling lonely, since alone describes a state of being and lonely describes an emotional response to one’s circumstances. Most people don’t feel sad when they go to the bathroom by themselves, for instance.

alone:

As you can see, a person can be alone in the sense that no other people are present, or alone in the sense that he or she is unaccompanied, even in a crowd.

lone and alone:

Lone is another adjective with the same meaning as alone. It is a shortening of the word alone, but it has a different place in the English sentence.

SUMMARY:

Alone describes a state of isolation or solitude when one is outside the company of others.

Lonely describes a feeling of sadness or abandonment.

Lone is placed at front of a noun, and alone is used to be predicative or adverb

總結：

alone 描述的一種獨自、沒有陪伴的狀態。

lonely 描述的是因 獨自或沒有陪伴狀態(alone)引起的情感上的感覺(feeling of sadness or abandonment)。

lone 通常放在名詞之前做形容詞，alone 做表語和副詞。

一句話記住兩個詞的區別：Loneliness is often, but not always, a result of being alone.

都是形容詞 但是強調的意思不同 alone 是指一個狀態，就是單獨的意思，alone at home,單獨在家，不強調主觀感受 lonely 則是孤獨的意思，強調一種感覺 舉例：我可能alone,但不一定lonely 我解釋的你能理解嗎？

lone“獨行”的意思，就是一個人去幹什麼lonely多指心靈的孤獨“孤單”的意思