1 means direct reference. (Quotations refer to words or idioms, aphorisms, poems, etc. Quote others in writing, including onomatopoeia and transliteration).
2. Represents a specific title. (Specific appellations refer to names, abbreviations, special terms and anniversaries with certain characteristics).
3. Express irony and negation. (also known as irony).
4. Express special meaning. Words in special meaning indicators have new meanings in their specific language environment.
5. Emphasize and attract attention.