Michele R. answered 1d
Veteran English Teacher | Structured Writing & Literary Analysis
A colon (:) is usually used to introduce something that explains, lists, or gives an example of what came before it. For example: I need three things: a pencil, paper, and a notebook.
A semicolon (;) is used to connect two closely related complete sentences. For example: I finished my homework; then I watched television.
The easiest way to remember the difference is: a colon introduces; a semicolon connects.