Grammar Help?

Question

I'm trying to use dashes to set off a piece of text in a paper, but I'm a little mixed up on the grammar. Which, if any of these, is correct?

Regardless of the fact that he received a passing grade on the assignment—apparently different font sizes and globs of glue weren’t a big enough giveaway—, he never advanced his critical thinking skills

- Or -

Regardless of the fact that he received a passing grade on the assignment—apparently different font sizes and globs of glue weren’t a big enough giveaway,— he never advanced his critical thinking skills

- Or -

Regardless of the fact that he received a passing grade on the assignment—apparently different font sizes and globs of glue weren’t a big enough giveaway, he never advanced his critical thinking skills

Answer 1

I you want to used the 3 em dash, use it on both ends of the phrase. Don't use both a comma and a dash as you've done in the first example. The idea is parallelism: either use two commas or two dashes, but don't mix them. There's no hard and fast rule about this; use of either dashes or commas is optional. The only rule is consistency.

Answer 2

Dashes are used for similar purposes to parentheses.

The closest to correct is the first one, but there is no need for the comma after the second dash. Also, use spaces between the dash and words.

Answer 3

how bout revising your sentence all over....frankly i'm confused with the message being conveyed by your comment....