When do we use the colon in English?
1) To introduce quotes
A colon can be used before a quote, especially if the quote is given on a separate line.
- A quote can be introduced like this:
Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote Quote
(Source)
2) Before a list
A colon can introduce a list in a sentence.
- A list can be introduced like this: item, item,item.
3) Before an explanation
A colon can introduce an explanation.
- The police made several arrests: there was a lot of trouble after the match.
4) To separate titles from sub-headings.