也【yě】

In classical Chinese, 也 at the end of a sentence says that what came before it is a statement of fact or a definition. Early classical prose doesn't link two nouns with 是 – there 是 means "this" – so the topic comes first, often marked with 者, and 也 closes the comment. In modern Chinese it turns up in quotations, set phrases and deliberately bookish writing.

Explaining and judging

也 also closes a sentence that gives a reason or a verdict, not only a definition. 非…也 denies one.

Still in use

Modern writers borrow it for weight: 此非一日之功也 "this is not the work of a single day". 何也 asks "why is that?" in an essay, and 非也非也 "no, no" is a jokey denial in speech.

Final 也 is not "also"

Modern 也 "also" goes before the verb. A 也 that ends the sentence is the classical one, and reading it as "also" garbles the line: 是知也 is "this is knowing", not "is also knowing". Classical "also" is 亦, before the verb.