- Introduces a quotation
- Mary gave advice to her children: a stitch in time saves nine.
- Patient: Is there a doctor in here?
- Introduces a sentence with the role of apposition with respect to the previous one
- Luruns could not speak: he was drunk
- Introduces the logical consequence, or effect, of a fact stated before
- There was only one possible explanation: the train had never arrived
- Separation of clauses in a periodic sentence