What you'll learn
This lesson covers sentence structure — how words, phrases and clauses fit together into clear, complete sentences. You will learn to find and fix:
- Run-ons and comma splices — two sentences jammed together.
- Fragments — pieces that are not complete sentences.
- Misplaced and dangling modifiers — describing words in the wrong place.
- Faulty parallelism — lists and pairs that do not match.
- Weak subordination and coordination — joining ideas with the wrong connector.
- Transitions — words like however and as a result that show how ideas connect.
How it appears on the GED. Sentence-structure items appear inside the RLA test as drop-down menus in edited documents (memos, emails, notices, reports). Each menu offers several versions of a phrase, and only one makes the sentence complete, clear and logical. Other items quote one or two sentences from a passage and ask which revision or combination is best. These questions reward one habit above all: find the subjects and verbs.
Key terms
- clause — a group of words with a subject and a verb (the bus arrived).
- independent clause — a clause that can stand alone as a sentence (The bus arrived late.).
- dependent (subordinate) clause — a clause that cannot stand alone; it begins with a word like because, when, although, if, who, which (because the bus arrived late).
- run-on (fused sentence) — two independent clauses with no punctuation between them (The bus was late I walked.).
- comma splice — two independent clauses joined by only a comma (The bus was late, I walked.).
- fragment — a group of words punctuated as a sentence but missing a subject, a verb, or a complete thought (Because the bus was late.).
- coordinating conjunction (FANBOYS) — for, and, nor, but, or, yet, so; joins equal ideas.
- subordinating conjunction — because, although, when, while, if, unless, since, after, before; makes one idea depend on another.
- conjunctive adverb — however, therefore, consequently, moreover, nevertheless; shows a relationship but cannot join sentences with a comma alone.
- modifier — a word or phrase that describes something (Covered in snow, the car…).
- dangling modifier — a modifier with no sensible word to describe in the sentence.
- misplaced modifier — a modifier placed next to the wrong word.
- parallelism — using the same grammatical form for items in a list or pair (to read, to write, and to speak).
- transition — a word or phrase that shows the logical link between ideas (for example, as a result).
1. Run-ons, comma splices and fragments
Every sentence needs at least one independent clause: a subject, a verb and a complete thought.
Run-ons and comma splices happen when two independent clauses are joined incorrectly:
- Run-on: The lot is full you can park on Elm Street.
- Comma splice: The lot is full, you can park on Elm Street.
Four correct fixes:
| Fix | Example |
|---|---|
| Period | The lot is full. You can park on Elm Street. |
| Semicolon | The lot is full; you can park on Elm Street. |
| Comma + FANBOYS | The lot is full, so you can park on Elm Street. |
| Subordinate one clause | Because the lot is full, you can park on Elm Street. |
Watch out for however and therefore. They are not conjunctions. Wrong: The lot is full, however, Elm Street has spaces. Right: The lot is full; however, Elm Street has spaces.
Fragments are missing something:
- No subject: Called the office twice. → She called the office twice.
- No complete verb: The manager reviewing the schedule. → The manager is reviewing the schedule.
- A dependent clause alone: Because the warehouse is cold. → Bring a jacket because the warehouse is cold.
- A phrase alone: Especially on weekends. → The store is busy, especially on weekends.
Fix a fragment by attaching it to a nearby sentence or adding the missing part.
2. Misplaced and dangling modifiers
A modifier should sit right next to the word it describes.
Dangling modifiers usually open the sentence with an -ing or -ed phrase. The noun right after the comma must be the one doing that action.
- Wrong: After reviewing the budget, the plan was approved. (The plan did not review the budget.)
- Right: After reviewing the budget, the board approved the plan.
- Also right: After the board reviewed the budget, it approved the plan.
Misplaced modifiers are in the wrong spot, creating a silly or unclear meaning.
- Wrong: We sold the desk to a customer with broken drawers. (The customer has broken drawers?)
- Right: We sold the desk with broken drawers to a customer.
- Wrong: The manager almost called every employee. (She almost called, but didn't?)
- Right: The manager called almost every employee.
Limiting words such as only, almost, just, nearly change meaning depending on where they go: Only Ana works Sundays (no one else) vs. Ana works only Sundays (no other day).
Two-step fix: (1) Ask "Who or what is doing or being described?" (2) Put that word right next to the modifier, or turn the modifier into a full clause with its own subject.
3. Parallelism
Items joined by and, or, but, or in a list, must use the same grammatical form.
| Not parallel | Parallel |
|---|---|
| She likes cooking, to swim, and reads. | She likes cooking, swimming, and reading. |
| The job requires lifting boxes, working weekends, and you must drive. | The job requires lifting boxes, working weekends, and driving. |
| The plan will save money and time will be saved. | The plan will save money and time. |
| Not only is it cheap but also it works fast. | It is not only cheap but also fast. |
Paired connectors need parallel parts too: either … or, neither … nor, both … and, not only … but also. Whatever follows the first word must match what follows the second: You can either call the office or send an email (verb … verb).
How to check: stack the items vertically.
- train new cashiers
- order supplies
- schedule weekend shifts ✓
If one item starts with a different kind of word (an -ing word, a noun, a new subject), it breaks the pattern.
4. Subordination, coordination and transitions
Connectors tell the reader how ideas relate. Choosing the wrong one makes a sentence illogical even when the grammar is fine.
| Relationship | Subordinating conjunctions | Transitions (conjunctive adverbs) | FANBOYS |
|---|---|---|---|
| Cause / result | because, since | therefore, as a result, consequently | so, for |
| Contrast | although, even though, while | however, nevertheless, on the other hand | but, yet |
| Time | when, after, before, until | then, afterward, meanwhile | — |
| Condition | if, unless | otherwise | or |
| Addition | — | also, in addition, furthermore | and |
| Example | — | for example, for instance | — |
Coordination joins equal ideas: The shop is small, but it is busy.
Subordination makes one idea depend on the other and often shows the relationship more precisely: Although the shop is small, it is busy.
Punctuation reminders:
- Subordinate clause first → comma: When the alarm sounds, leave the building.
- Subordinate clause last → usually no comma: Leave the building when the alarm sounds.
- Transition between two sentences → semicolon or period before, comma after: Sales rose; as a result, we hired two clerks.
To choose a transition, cover the options and say the relationship in one word: cause? contrast? example? addition? time? Then pick the option that matches.
Worked example 1 — fixing a comma splice
Email: The copier on the second floor is broken ___ please use the one in the lobby.
Question: Choose: broken, please / broken please / broken; please / broken, however, please
Think-aloud:
- "The copier on the second floor is broken — that's complete. Please use the one in the lobby — that's a complete command too (the subject you is understood)."
- "Two complete sentences need a period, a semicolon, or a comma + FANBOYS."
- "broken, please is a comma splice. broken please is a run-on. broken, however, please is still a splice — and however would signal contrast, which doesn't fit."
Answer: broken; please.
Worked example 2 — a dangling modifier
Report: Running late for the meeting, ___.
Question: Choose:
A. the elevator was too slow for Kevin
B. Kevin took the stairs to the third floor
C. the stairs were taken by Kevin
D. the third floor was reached by Kevin
Think-aloud:
- "Who was running late? A person — Kevin."
- "So the word right after the comma must be Kevin."
- "A puts the elevator first: the elevator was running late? No. C and D start with the stairs and the third floor — also wrong."
- "Only B begins with Kevin."
Answer: B.
Worked example 3 — parallel structure in a job posting
Job posting: The ideal candidate will greet customers, answer phones, and ___.
Question: Choose: handling cash / handle cash / cash handling is required / will be handling cash
Think-aloud:
- "The pattern: will greet … answer … — base verb + object."
- "The third item should also be base verb + object: handle cash."
- "Handling cash is an -ing form. Cash handling is required is a whole new clause. Will be handling cash repeats will and changes the verb form."
Answer: handle cash.
Worked example 4 — choosing the logical connector
Notice: The pool will close at 4:00 p.m. on Friday. ___, the lifeguards will attend a safety training.
Question: Choose: For example / During that time / Nevertheless / Similarly
Think-aloud:
- "What's the relationship? The pool closes, and while it is closed the lifeguards are at training. That's time."
- "For example would make the training an example of the closing — no. Nevertheless signals contrast — nothing is contrasted. Similarly compares like ideas — no."
- "During that time shows the time connection and explains why the pool closes."
Answer: During that time.
Common traps
- Fixing a comma splice with however. Wrong: We are closed Monday, however, we open Tuesday. Right: We are closed Monday; however, we open Tuesday.
- Thinking a long sentence must be a run-on. Length is not the test. A long sentence with one independent clause, or two clauses joined correctly, is fine. A short one (It rained we left.) can be a run-on.
- Thinking because sentences are always fragments. Because clauses are fine when attached to a main clause: We left early because it rained.
- Moving a dangling modifier to the end. Wrong: A schedule will be sent to you after completing orientation. Still no one completes orientation. Name the person: After you complete orientation, we will send you a schedule.
- Fixing only part of a list. Changing one item to match another but leaving a third item out of pattern still breaks parallelism.
- Choosing a transition that sounds formal instead of logical. Moreover and Consequently sound impressive, but they are wrong if the sentences contrast.
Test-day strategy
- Mark the subjects and verbs. In your head, underline every subject-verb pair. Count the independent clauses and check how they are joined.
- Read the sentence before and after. Transitions depend on the previous sentence; fragments often belong to the sentence next to them.
- Ask "who is doing this?" for every opening phrase that ends in a comma.
- Stack list items to check parallelism.
- Name the relationship in one word (cause, contrast, time, example, addition) before looking at transition choices.
- Eliminate options that create a new error. A choice might fix the run-on but add a fragment, or fix the modifier but change the meaning.
- Budget your time. Drop-down items should take about a minute each. Answer every one — there is no penalty for guessing.
Check yourself
Read the notice. Then choose the option that correctly completes the sentence.
Lakeview Apartments — Package Policy
The front desk closes at packages delivered after that time will be held in the mailroom until the next morning.
Choose an answer from each menu.
Hint
Both halves of this sentence could stand alone. What is needed to join two complete sentences correctly?
Step-by-step solution
The sentence contains two complete thoughts: The front desk closes at 5:00 p.m. and packages delivered after that time will be held in the mailroom. Each has its own subject and verb (desk closes; packages will be held), so each is an independent clause. Two independent clauses cannot simply be pushed together or joined with only a comma.
Step by step:
- Find the two clauses and the place where they meet (after 5:00 p.m.).
- Join them correctly with a comma plus a coordinating conjunction. The second idea is a result of the first, so so fits: 5:00 p.m., so packages…
- Reject the others: no punctuation creates a run-on; a comma alone creates a comma splice; so, with the comma after it puts the comma in the wrong place.
The correct choice is 5:00 p.m., so.
Tip: Three ways to join two complete sentences: a period, a semicolon, or a comma + FANBOYS (for, and, nor, but, or, yet, so). A comma by itself is never enough.
Check yourself
Notice: Volunteer Orientation at Harbor City Food Bank
Harbor City Food Bank — Volunteer Orientation
(1) Thank you for signing up to volunteer with Harbor City Food Bank! Every week, our volunteers sort, pack, and deliver food to more than 3,000 families across the county. Before your first shift, you will attend a short orientation session at our warehouse on Pier Road.
(2) Orientation lasts about an hour, it covers safety rules, the sorting process, and the location of emergency exits. Sessions are held every Saturday at 9:00 a.m. and every Wednesday at 6:00 p.m. You do not need to register for a specific session. Simply arrive about ten minutes early and check in at the volunteer desk.
(3) Please dress for physical work. Wear closed-toe shoes and comfortable clothing that you do not mind getting dusty. From November through March, bring a warm jacket. Because the warehouse is unheated in winter. Gloves, hairnets, and safety vests will be provided. Please leave valuables at home, since lockers are not available.
(4) After completing orientation, a shift schedule will be emailed to you. You may choose morning, afternoon, or evening shifts, and you can change your schedule at any time through our online volunteer portal. Most shifts last three hours, and groups of up to ten people can volunteer together.
(5) Volunteers must be at least 14 years old. Volunteers who are 14 to 17 must have a permission form signed by a parent or guardian, and they must work alongside an adult volunteer. Court-ordered community service hours are welcome; please bring your paperwork to orientation so that our staff can sign it.
(6) We look forward to meeting you. Your time and energy make a real difference for neighbors who need help putting food on the table. If you have questions before your orientation, call our volunteer office at 555-0148 or send an email to the address on our website.
In paragraph 3, the notice says: "From November through March, bring a warm jacket. Because the warehouse is unheated in winter."
Which revision corrects the error in these sentences?
Hint
Read the second group of words by itself. Does it express a complete thought?
Step-by-step solution
Paragraph 3 says: "From November through March, bring a warm jacket. Because the warehouse is unheated in winter." The second group of words begins with Because, a subordinating conjunction. A clause that starts with because is dependent — it cannot stand alone. Read by itself, "Because the warehouse is unheated in winter" leaves the reader waiting: because… what? It is a fragment.
Step by step:
- Attach the fragment to the sentence it explains. The reason (unheated warehouse) explains the instruction (bring a jacket).
- When the because clause comes after the main clause, no comma is needed: bring a warm jacket because the warehouse is unheated in winter.
- Check the others: a semicolon needs a complete sentence on both sides, so it does not fix a fragment; a comma alone after Because leaves the fragment; deleting the warehouse removes the subject and makes things worse.
The correct answer is "From November through March, bring a warm jacket because the warehouse is unheated in winter."
Tip: Words like because, although, when, if, since, unless and while turn a clause into a dependent clause. If one starts a "sentence," make sure a main clause is attached.
Summary
- Join two independent clauses with a period, a semicolon, a comma + FANBOYS, or by subordinating one; never with a comma alone.
- A fragment lacks a subject, a verb or a complete thought; attach it to a nearby sentence or add what is missing.
- Put modifiers next to the words they describe; after an opening phrase, the next noun must be the doer.
- Keep items in lists and paired constructions in the same grammatical form.
- Choose connectors and transitions by the relationship they show: cause, contrast, time, condition, addition or example; however and therefore need a semicolon or period before them.