jill, thanks for catching those errors and using your sharp act english skills in the process. i’ve made some quick corrections to the grammar, punctuation and technical errors you spotted in this post. the post is now greatly improved, so that magoosh can practice what it preaches in this article.

however, i would also like to correct you on your statements about the act english descriptors. on the act’s page for english standards, they mention colons as an exam element (see standard pun 702), and they also have standards that don’t explicitly mention the use of dashes, but could potentially test dashes (see standards pun 503 and pun 602).

clauses
(examples: “i think i’ll try defying gravity,” “the sun’ll come out tomorrow,” [missing quotation mark] etc.)
dependent clauses have a subject and verb, but are not complete sentences.
(examples: “under the sea,” [not a clause] “if i only had a brain,” etc.)
independent—dependent clauses
you can use commas to separate independent clauses from dependent clauses [if and only if the dependent clause comes first].

colons
q [not tested-see the act descriptors]

semicolons
semicolons are great. they’re my favorite punctuation mark—no, seriously. they’re sophisticated; use them properly, and people will be impressed at your mastery of the english language.
here are the rules for semicolons:
• use a semicolon to separate two closely related independent [what…?] when i say “closely related,” i mean that they clearly belong as part of the same thought. the two sentences are grammatically complete, but make much more sense when joined together.

wait! what about hyphens? [not in act descriptors.]

apostrophes
plural possessive
…but if multiple teams share a bus, it’s the “teams’ bus.” this is because for plural nouns, the apostrophe comes after the “s”. so “the girls’ jackets” let’s [incorrect apostrophe use] us know we are talking about multiple girls with multiple jackets, not one girl with an envious [enviable] boatload of jackets (that would be “girl’s jackets”).