Well-known means a lot of people know it — a person, a place, a fact, a shop, a song. It works two ways that are worth separating.

Well-known means意思是 a lot of people know it很多人知道它——a person一個人、a place一個地方、a fact一件事、a shop一家店、a song一首歌。It works two ways它有兩條路子，that are worth separating值得分開看。

About people and things, it is close to famous but calmer and smaller in scale: a well-known author is known to readers, a famous author is known to everyone. It also takes a boundary very naturally — "well-known in Taipei", "well-known among doctors" — which famous resists.

About people and things用在人和事物上，it is close to famous它接近 famous，but calmer and smaller in scale但更平靜、範圍更小：a well-known author一位 well-known 的作者，is known to readers是讀者認識的；a famous author一位 famous 的作者，is known to everyone是所有人都認識的。It also takes a boundary very naturally它也很自然地能帶一個範圍——“well-known in Taipei”在台北很有名、“well-known among doctors”在醫生圈子裡很有名——which famous resists這是 famous 不太肯做的事。

About facts, it means everybody already knows this, so I am not going to argue for it: "it is well-known that sleep affects memory". Writers lean on that phrase, sometimes to slip an unproven claim past you, so it is worth reading with a raised eyebrow.

About facts用在事實上，it means它的意思是：everybody already knows this大家早就知道這件事，so I am not going to argue for it所以我就不再論證了：“it is well-known that sleep affects memory”「睡眠影響記憶，是大家都知道的」。Writers lean on that phrase寫文章的人很愛靠這個句型，sometimes to slip an unproven claim past you有時是想讓一個沒證明過的說法從你眼前溜過去，so it is worth reading with a raised eyebrow所以讀到它，值得挑一下眉。

It is neutral about good and bad — you can be well-known for kindness or for cheating — though when the reason is bad, English often prefers notorious.

It is neutral about good and bad它對好壞是中立的——you can be well-known你可以有名，for kindness因為善良，or for cheating或因為騙人——though不過，when the reason is bad當原因是壞事時，English often prefers notorious英文常改用 notorious。

Before a noun it takes a hyphen; after be, both "well known" and "well-known" are written, and either is accepted. The comparative is better-known / best-known, not "more well-known", which sounds wrong to native ears even though you will hear it.

Before a noun在名詞前，it takes a hyphen要加連字號；after be在 be 動詞後面，both “well known” and “well-known” are written兩種寫法都有人寫，and either is accepted也都被接受。The comparative is比較級是 better-known / best-known，not “more well-known”不是 “more well-known”，which sounds wrong to native ears那在母語者耳裡聽起來是錯的，even though you will hear it雖然你還是會聽到有人講。