2.3 Apostrophes, Dashes, and Parentheses

Small Marks, Big Consequences

Apostrophes, dashes, and parentheses can change meaning quickly. ACT English uses them inside passages where you must protect both sentence grammar and the writer's purpose. These marks are not decorative. An apostrophe can change a plural noun into a possessive noun; a dash can make a detail feel emphatic; parentheses can push information into the background.

Before choosing an answer, ask two questions. First, what job does the mark perform in the sentence? Second, is the material affected by the mark essential to the meaning? Those questions prevent most errors with ownership, contractions, and interrupting information.

Apostrophes: Possession and Contractions

An apostrophe has two main ACT jobs: possession and contraction. For most singular nouns, add apostrophe-s: the artist's notebook. For regular plural nouns ending in s, add only an apostrophe: the artists' notebooks. For irregular plurals that do not end in s, add apostrophe-s: the children's notebooks.

Use this table when a noun near an apostrophe is underlined:

The most common ACT trap is its versus it's. It's means it is or it has. If you cannot substitute it is or it has, use its. The committee revised it's plan is wrong because the sentence means the plan belonging to the committee. The correct form is its plan if the committee is treated as an entity, or the committee's plan if the noun is repeated for clarity.

Do not add apostrophes to possessive pronouns: ours, yours, hers, theirs, its, and whose. Theirs' and who's proposal are wrong when possession is intended. Who's means who is or who has; whose is possessive.

Dashes: Emphasis and Interruption

A dash sets off a break in the sentence. On ACT English, a dash can introduce an explanation after a complete thought, create emphasis, or frame nonessential material. It is stronger and more noticeable than a comma. The final obstacle was unexpected - a locked storage room beneath the stage uses a dash to emphasize the explanation.

When dashes come in pairs, the material between them should be removable. The mural - painted during a week of rain - still shows bright color works because the core sentence remains complete: The mural still shows bright color. If one dash opens an interruption, a matching dash or equivalent closing punctuation must complete the structure. ACT answer choices often leave one dash stranded.

Dashes can overlap with commas or parentheses, but tone matters. Commas are neutral, dashes are emphatic, and parentheses are quiet. If the passage is formal and the detail is simply nonessential, commas may be smoother than dashes. If the writer is highlighting a surprising clarification, a dash may fit best.

Parentheses: Quiet Nonessential Asides

Parentheses set off information that is related but not central. The sentence must remain grammatical if the parenthetical material is removed. The observatory reopened in May (two months ahead of schedule) after a volunteer repair effort works because the core sentence is complete without the aside.

Parentheses are wrong when they hide information needed by the sentence. The observatory reopened in (May) after a volunteer repair effort is awkward because May is the object of in and belongs in the main sentence. Parentheses are also poor choices when the information is the main point of the sentence. ACT English usually prefers clear integration over unnecessary parenthetical clutter.

Choosing Among Similar Marks

ACT-Style Examples

Consider: The laboratories safety checklist was revised after the inspection. The issue is possession. One laboratory owns the checklist, so the revision should be The laboratory's safety checklist was revised after the inspection. If several laboratories share one checklist, The laboratories' safety checklist would be correct. The sentence's meaning controls the apostrophe position.

Now consider: The grant funded one final purchase (a portable scanner) that allowed the archive to digitize fragile maps. The parenthetical phrase is acceptable only if the sentence still reads cleanly without it: The grant funded one final purchase that allowed the archive to digitize fragile maps. That works, but the answer set may prefer commas or dashes depending on emphasis. If the scanner is the key new information, integrating it directly may be clearer: The grant funded one final purchase, a portable scanner that allowed the archive to digitize fragile maps.

Common Traps

1. Choosing it's for possession because apostrophes usually show ownership.
2. Adding an apostrophe to a regular plural that does not own anything.
3. Using one dash when the sentence needs a matched pair around an interruption.
4. Putting essential information inside parentheses.
5. Choosing dramatic dashes when the passage uses a restrained academic tone.

When you see these marks, read the core sentence without the inserted material. If the grammar collapses, the material is essential and should not be hidden. If the grammar survives, choose the mark that best matches the emphasis and style of the passage.