Colon: usually indicates a pause after a prompt or a prompt below or a summary above.

Dash: As the name implies, it is a punctuation mark indicating "break" and "fold". The so-called "breaking" means suddenly interrupting the dialogue in the sentence; The so-called "folding" is to transfer the meaning to the other side. It means pause, turn around and comment.

2. The relationship between general statement and specific statement is different.

If the sub-sentence part is an item-by-item explanation or enumeration of the general sentence, please use a colon.

If the sub-statement is an explanation of the general statement, a dash should be used.

Example:

The following programs will be performed tonight: dance, solo, duet, cross talk and sketch.

China's four great inventions-gunpowder, printing, compass and papermaking have made great contributions to the development of world history.

3. Different tones

When all statements and some statements are represented by colons, the pause in the middle is slightly longer.

When using dashes to express comments, there is no pause time or the pause is quite short.