A man may usually be known by the books he reads as well as by the companies he keeps, for there is a companionship of books as well as of men.

書上的句子。

1）是不是應該by the company he keeps, 復數用錯誤？

2) 請教老師company, companion, companionship 這3個單詞作伴隨之類意思時，到底有什么不同？

1 company表示“伴隨”意義時，為不可數名詞，所以用復數為錯誤，應刪去S。

2 companion為可數名詞，意為：朋友、伙伴、同伴。companionship, 可數名詞加詞尾 - ship, 將可數名詞變為抽象名詞，表示關系。比如，friendship, partnership, companionship, relationship 具體你可查詞典。