1. Verb | "be; exist" 是, meaning "be; exist", is used to connect nouns and to identify the subject.
2. Verb | 是-的 The element between 是-的 can be a verbal phrase or an adjective.
3. Verb | Negation of 是-的(1) Only 不 can negate sentences that contain 是-的. 没 can not negate 是.
4. Verb | Negation of 是-的(2) The negative form of modal verbs can be placed between 是-的.
5. 根本"at all"/毕竟"after all"-不是 根本"at all"/毕竟"after all" can be placed before 不是 to emphasize the negation.
6. Conj.| 还是 "or" 还是 is used to offer choices. When more than two options are offered, 还是 is placed between the last 2 options.
7. Conj.| 不是-就是 "either-or" The conjunction 不是-就是 means "either-or" which connects two choices.
8. Conj.| 要是-(的话) "if" The conjunction 要是 means "if". In casual speech, 要是 can be 要是-的话。 When 的话 is used, 要是 becomes optional.
9. Conj.| 不是-而是 不是-而是 means "not A, but rather B." 是-而不是 means "is A, but not B."
10. Conj.| 但是;可是 "but" The conjunctions 但是 and 可是 mean "but".
11. Conj.| 是因为 "because" The Causal Conjunction 是因为 means "because".
12. Conj.| 于是 "so" The conjunction 于是 means "so".
13. Question:是不是 "isn't it" The affirmative-negative phrase 是不是 can be used to ask a tag question. 是 with the modal particle 吧 used at the end of a sentence to express interrogation.
14. Adv.| "yes" 是 alone can give a positive answer.
15. 是否 "whether" 否 means "no". 是否 is a formal version of 是不是, meaning "whether".
16. 总是,老是 "always" The adverbs 总是 and 老是 mean "always".
17. With 都"all"，也"also" 也 means "also". 都 means "all". Both are adverbs. They can be placed before 是, but they cannot precede a noun or a pronoun.
