TEAS punctuation rules: commas, semicolons and apostrophes with worked examples

Where punctuation fits on the test

Spelling, punctuation and sentence structure are the three objectives in the conventions area of ATI's TEAS 7 content outline, and together they share 12 scored questions. ATI does not publish how many are punctuation alone.

Punctuation and sentence structure overlap heavily. Whether a comma is right often depends on whether it joins two complete clauses, so if clauses are new to you, read our sentence structure guide first and come back. The independent clause check below is the same idea in a punctuation setting.

Commas: the four decisions that matter most

Purdue OWL lists eleven comma rules. Four decide most answer choices. Put a comma before and, but, for, or, nor, so or yet when it joins two independent clauses. Put a comma after an introductory clause, phrase or word. Use a pair of commas around information that is not essential to the meaning. Do not use commas around essential information, such as a clause beginning with that.

The essential test is the one most applicants guess on. Compare the nurse who works nights covers this unit with Dr. Lee, who works nights, covers this unit. In the first, the clause tells you which nurse, so removing it changes the meaning and it takes no commas. In the second, the name already identifies the person, so the clause is extra and needs a comma on each side. A single comma where a pair belongs is a common wrong option.

Lists are simpler: separate three or more items in a series with commas. A comma between a subject and its verb, as in the medication on the cart, was expired, is not correct, however natural the pause sounds.

Semicolons and the however trap

Purdue OWL gives two uses that matter here. A semicolon joins two independent clauses with no connecting word: the patient refused breakfast; she ate lunch. It also joins two independent clauses linked by a conjunctive adverb such as however, therefore, consequently or nevertheless, with a comma after the adverb.

The trap is a comma in front of however. The patient refused breakfast, however, she ate lunch is a comma splice, because both halves are complete sentences and a comma cannot hold them together. The fix is a semicolon before however or a period. If the word after the mark is and, but or so, a comma is right instead, because those are coordinating conjunctions, not conjunctive adverbs.

Apostrophes: possession, contractions and its

For a singular noun, add an apostrophe and s, even when the word already ends in s, according to Purdue OWL. For a plural noun ending in s, add only the apostrophe: two cats' toys, the nurses' station when it belongs to several nurses. For joint ownership, only the last name takes the apostrophe: Todd and Anne's apartment.

Apostrophes also mark missing letters in contractions, so it's means it is or it has, while its is the possessive and takes no apostrophe, the same as his and hers. One narrow exception to the no-apostrophe-for-plurals rule exists: OWL uses an apostrophe to pluralize lowercase letters, as in mind your p's and q's. Ordinary plural nouns never take one, so patient's charts for several charts is wrong.

Sources

ATI: ATI TEAS Version 7 Content Outline. Punctuation objective within the 12-question conventions of standard English area

Purdue OWL: Commas, Quick Rules. Eleven comma rules including conjunctions, introductory elements, nonessential and essential elements, series

Purdue OWL: Commas vs. Semicolons in Compound Sentences. Semicolons join independent clauses with no connector or with conjunctive adverbs such as however and therefore

Purdue OWL: Apostrophe Introduction. Singular and plural possession, joint possession, contractions, its versus it's, lowercase letter plurals