Using dash: Mohammad, which category do you fall into -- do you belong to the.

Hello,
could anyone clarify that when and how"–" is used? such as follow:

"Mohammad, which category do you fall into – do you belong to the "

Thanks in advances,
Mohammad,

Hello Mohammad,

Sorry, but I do not understand your problem. Could you give more detail?

Thanks.

Hi Mister,
there are many cases in Torsten emais in which he used “–” in the essays such as the sentence below:

“which category do you fall into – do you belong to the…”
I mean the punctuation rule for using “–” in writing.

Ah, I see. You are asking about the m-dash. It is used in less formal writing, instead of a colon, usually. Here are Harvard University’s brief comments:

[i]When you’re setting off a clause—this one is a good example—use the m-dash. (You can indicate this dash with two hyphens–like this–if you don’t have an m-dash function on your computer.) Be sure that the parts of the sentence that precede and follow the dashes would make sense even if you removed the dashes and the words they bracket. (In the example above, the sentence is readable with or without the clause inside the dashes.)

You can also use the m-dash in place of a colon if you want to emphasize more dramatically the words that follow: “The mantle piece was lined with photographs of people she loved—her mother, her grandmother, a favorite aunt.” Or you can use it to add a surprising element into a sentence: “Her family’s photographs were displayed on the mantle piece; there were pictures of parents, grandparents, and siblings—and of Muffin, a Yorkshire terrier.” Whereas the m-dash is used to set off parts of a sentence, hyphens are used to join words together: broken-hearted, two-thirds, sister-in-law.[/i]

good explanation