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ATI TEAS Punctuation: Commas, Apostrophes, and Sentence Boundaries
TEAS punctuation items ask which mark makes the sentence grammatical. Decide whether you have two independent clauses, a list, or a possessive before you pick a comma.
Short answer
Punctuation on ATI TEAS 7 sits inside Conventions of Standard English (12 scored items in English & Language Usage). The usual task is to choose the mark that creates a complete, correctly bounded sentence: commas in lists and after introductory elements, apostrophes for possessives versus contractions, and the difference between a comma splice and a legal join of two independent clauses. The busiest-looking sentence is not the correct one.
Pick the mark that finishes the sentence, not the busiest one
Punctuation items on TEAS English reward the mark that makes the sentence grammatical, not the one that looks busiest. Find the subject and the complete verbs before you touch a comma. English & Language Usage is the section map (37 items, 37 minutes, 12 scored convention items). This page is execution: boundaries, commas, apostrophes.
English time is about one minute per item. You cannot diagram every sentence. You can still name the structure.
Independent clauses are the fork in the road
If both sides could be their own sentence, a comma alone is a comma splice. Legal joins include a period, a semicolon, or a comma plus a coordinating conjunction (and, but, or, so, yet, for, nor).
Original example (Passy): “The lab closes at five the night staff continues processing.”
That needs a boundary: period, semicolon, or “, and”. A lonely comma is the trap.
If one side cannot stand alone—“After the lab closes”—you have an introductory element. A comma after that phrase is often required. A semicolon would be wrong because the first part is not independent.
Lists of three or more parallel items take commas. Do not add a comma between a subject and its verb just because the subject is long.
These examples are original teaching sentences. They did not appear on a live TEAS.
When splice versus fragment still swaps, use items that only change whether the second half can stand alone.
Apostrophes are spelling with a job
Possessive: the technician’s badge (one technician), the technicians’ lounge (more than one). Contraction: it’s = it is. Possessive pronoun: its = belonging to it. No apostrophe.
Do not use an apostrophe to make a simple plural: patients, 1990s, CBCs.
Quotation marks follow the item’s own sentence. If the stem is testing quotes, close them and attach the comma or period the way the conventions item requires. Guessing from a social-media style will miss.
Reading will not save a comma splice. Different section, different clock.
A 20-second attack order
- Can each half stand as a sentence?
- Is this a list, an intro phrase, or a nonessential clause?
- Is the apostrophe possessive, contraction, or a fake plural?
- Eliminate the choice that creates a fragment or a splice.
What is on the TEAS reminds you that 20 items on the whole exam are unscored. You still answer every punctuation item as if it counts.
When the same splice miss repeats, keep a conventions-only English block.
The study guide and Guides hub are the rest of prep. Punctuation is one mechanic.
After the rule is reliable, drop comma-splice items into mixed English practice so they still hold when vocabulary stems sit next to them.
Trust the source
Official sources
Exam policies can change. Use these primary sources for the most current details.