verb, expression, place name, pronoun, numeral, adjective, conjunction, descriptive, noun, organization, adverb, particle, idiom, directional, punctuation, measure word, modal particle, preposition · to be; linking verb used to connect a subject with a noun or noun phrase

我是老师。

adverb, verb, noun, numeral, pronoun, preposition, punctuation, descriptive, measure word, particle, adjective, time word, place name, idiom · the copula verb used to link a subject to its predicate, indicating existence, classification, or identity.

他是一名医生。

verb, adverb, punctuation, conjunction, noun, particle · adverb used for emphatic assertion

天气是很冷。

verb · respectful acknowledgement of a command; very well

是，我这就去办。

verb · correct; right; true

你说得很是。