Sentence Boundaries

This is Unit Three of College Composition. Unit Two ended by choosing a sentence structure to match meaning. This unit looks at the edges of sentences, where one ends and the next begins. Carry one idea through this lecture. A boundary error is not only a grammar problem; it blurs how ideas relate, so the best fix is the one that states the relationship the writer means. Two worked examples at the end test that idea. By the end you will be able to find and fix sentence fragments. To find and fix comma splices and run-ons five ways. To check a paragraph sentence by sentence. And to choose among corrected versions by meaning.

Five entries on fragments: what they lack, the three common kinds, and the two ways to fix them.

Punctuated as a sentence, but not one.

CMP 0051 Sentence Fragments

A sentence fragment is punctuated as a sentence but lacks a subject, a verb, or both, or is a dependent clause standing alone. "Because the funding ran out." looks like a sentence but leaves the reader waiting for the main clause. Most fragments are errors in academic writing, so treat any fragment as a problem unless its purpose is unmistakable.

The commonest fragment.

CMP 0052 Dependent-Clause Fragments

The commonest fragment is a dependent clause, beginning with a word like because, although or which, set off as its own sentence. "Enrollment fell. Although tuition stayed the same." The second group has a subject and verb, but although makes it depend on another clause. Fix it by attaching it to the sentence it explains: "Enrollment fell, although tuition stayed the same."

A phrase standing alone.

CMP 0053 Phrase Fragments

A phrase set off as a sentence is a fragment, because a phrase lacks a subject, a verb, or both. Fragments often follow the sentence they expand: "Expenses kept rising. Things like rent, childcare and transportation." Lists introduced by things like, such as or for example are a frequent source of phrase fragments.

No working verb.

CMP 0054 Missing-Subject and Missing-Verb Fragments

Some fragments lack a working verb, often because an i n g word or a with phrase stands in for one. "With many families reporting higher costs." has no verb that a subject performs; "Many families reported higher costs" does. Read each sentence alone and ask who did what; if there is no answer, it is a fragment.

Two ways to fix a fragment.

CMP 0055 Fixing a Fragment

There are two main ways to fix a fragment: attach it to the sentence it belongs to, or rewrite it as a complete sentence. Find the sentence it depends on; most fragments follow the sentence they expand. If it adds detail, attach it with a comma or a connecting word. If it carries a separate idea, give it a subject and a verb. If it is a dependent clause, attach it or remove the subordinating word. Removing because or although fixes the grammar but can delete the relationship the writer meant, so when the reason matters, attach the clause instead.

Five entries on comma splices and run-ons, the five ways to fix them, and the transitional words that need a semicolon.

A comma alone between two sentences.

CMP 0056 Comma Splices

A comma splice joins two complete sentences with only a comma. "The survey closed on Friday, the results arrive next week." Each side could stand alone, so a comma is not strong enough to join them. Comma splices sound natural when read aloud, which is why they survive drafting; check every comma that sits between two clauses.

Two sentences fused.

CMP 0057 Run-On Sentences

A run-on sentence, also called a fused sentence, runs two or more complete sentences together with no punctuation between them. "Parents do not expect a reward they care for their children out of love." Two sentences meet at reward they with nothing to separate them. Run-on names this specific error, not a sentence that is merely long.

Five repairs for one error.

CMP 0058 Five Ways to Fix a Splice or Run-On

Comma splices and run-ons are fixed the same five ways. Add a comma and a coordinating conjunction. Use a period to make two sentences. Use a semicolon when the ideas are closely related. Use a semicolon with a transitional word such as as a result. Or turn one clause into a dependent clause, beginning with a word like because. Each fix is grammatical, but each says something slightly different about how the ideas connect. A comma plus however is not one of the fixes, because however is a transitional word, not a conjunction.

Picking among the fixes.

CMP 0059 Choosing the Right Fix

The best fix for a splice or run-on is the one that states the relationship the writer means. Use a period for separate points, a semicolon for close ones, a conjunction or transition for a stated link, and subordination when one idea explains another. On the exam, two choices may both be grammatical; pick the one whose connecting word fits the meaning.

Transitions between clauses.

CMP 0060 Conjunctive Adverbs Need a Semicolon

Words such as however, therefore, consequently and moreover do not join clauses on their own. "Prices rose, however, demand held steady" is a comma splice; "Prices rose; however, demand held steady" is correct. Inside a single clause, however takes commas only: "Demand, however, held steady."

Four entries on checking a whole paragraph: deliberate fragments, a step-by-step check, boundaries and meaning, and why long is not the same as run-on.

Fragments on purpose.

CMP 0061 Intentional Fragments

Writers sometimes use a fragment on purpose, to force quick reading or to stress a single image. Intentional fragments are most common in creative writing and advertising, as in "The rabbit darted out. A flash of movement." In academic writing, a deliberate fragment must be unmistakably deliberate; most readers will take it as an error.

A paragraph, sentence by sentence.

CMP 0062 Spotting Boundary Errors in a Paragraph

Boundary errors are easiest to find by checking a paragraph one sentence at a time. Read each sentence alone, from capital letter to end mark, and ask whether it has a subject and verb and can stand alone. Count its independent clauses, and check what joins them: a period, a semicolon, or a comma with a coordinating conjunction is correct; a comma alone is a splice; nothing at all is a run-on. Check sentences that begin with because, although, which or such as. Reading backward, last sentence first, helps you see grammar instead of meaning.

Errors that blur meaning.

CMP 0063 Boundary Errors and Meaning

Boundary errors are not only grammar problems; they blur how ideas relate. "The study was small, its results were promising" leaves the reader to guess the link; "Although the study was small, its results were promising" states it. When fixing an error, choose a connection that is true to the source; do not add a cause the writer never claimed.

Length is not the test.

CMP 0064 Long Is Not the Same as Run-On

A long sentence can be perfectly correct, and a short one can be a run-on. "I ran I fell" is a run-on in four words, while a sixty-word compound-complex sentence can be joined correctly throughout. Do not break a correct long sentence merely because it is long; break it if readers lose the main point.

Two worked examples: a paragraph with three boundary errors, and four corrected versions of one sentence. The opening idea is paid off at both.

Three errors in one paragraph.

CMP 0065 A Paragraph With Three Boundary Errors

A worked example, constructed for this course, pays off the opening idea. A draft about a town pool has three boundary errors. A sentence beginning with because has no independent clause, so it is a fragment; since it gives the reason for closing the pool, it is attached to the sentence before. Two clauses joined by a comma alone form a splice; the second adds detail, so a comma and and fit. Two clauses with nothing between them form a run-on; the hearing explains the delay, so one clause becomes dependent. Fixing every error with a period would produce a choppy paragraph and lose the connections. Each fix was chosen to state a relationship: reason, addition, condition.

Four corrections, one best.

CMP 0066 Choosing Among Corrected Versions

A second worked example, constructed for this course, starts from one comma splice about extended library hours and four corrections. Two periods are correct but leave the link implied. A semicolon with however is punctuated correctly, but however signals a contrast that is not there, so the meaning is wrong. A comma with and keeps the original meaning and supplies a fitting link. A version beginning with because states a cause, but it changes what the second clause claims. The method: confirm the grammar, test the connecting word against the meaning, and prefer the version that changes the writer's claim least. The most tempting wrong choice is usually grammatical.

Look at what you can now do. You can identify dependent-clause, phrase and missing-verb fragments, and fix them by attaching or completing them. You can identify comma splices and run-ons, and repair them with a conjunction, a period, a semicolon, a semicolon and a transition, or subordination. You can check a paragraph one sentence at a time, recognize a deliberate fragment, and tell a long but correct sentence from a run-on. And you can choose the correction that keeps the writer's meaning. Unit Four turns to the verb: forms, agreement, tense, mood and voice.