Punctuation in sentence structure

Question 1

Colons are used…

Answer 1

Used to introduce a list
To introduce an expansion (or an expansion of what has just been said
To introduce a question
To introduce a set of bullet points

Question 2

Semi-colons are used…

Answer 2

Joins two clauses
Usually to draw attention to the contrast
But sometimes, to point out the similarity
Separate items on a list

Question 3

It is wrong to use a semi-colon

Answer 3

To introduce a list (it can only separate items on the list)
To introduce a set of bullet points
To substitute for a comma simply because it looks nice

Question 4

Dashes are used…

Answer 4

To make an emphatic pause
To indicate an explanation (will follow like a colon but more dramatic)
To indicate hesitation or interruption

Question 5

Two dashes are used…

Answer 5

To separate a piece of information from the rest helps the reader to identify the main thread of the sentence