Sentence Structure — Core Skills

Sentence Structure: The Basics

Part 1 of 2 — Complete or Not Complete?

Every sentence-structure question comes down to one check: is this a complete sentence?

The building block: a clause

A clause is a group of words that has a subject and a verb.

• Subject = who or what the words are about.
• Verb = what the subject does or is.

"The students packed up" is a clause. The subject is the students. The verb is packed.

Two kinds of clauses

An independent clause can stand alone as a sentence. "The students packed up." Say it out loud and it feels finished.

A dependent clause has a subject and a verb but still cannot stand alone. Something is missing. What makes it dependent is the word it starts with:

because, although, since, when, while, if, unless, after, before, though

Add one of those words to the front and the clause stops being able to stand alone:

When the bell rang.

Subject: the bell. Verb: rang. But the word "When" leaves you waiting. When the bell rang, what happened? The thought is not finished.

The fragment

A fragment is a group of words punctuated like a sentence that is not actually a complete sentence. "When the bell rang." is a fragment. So is "Running down the street." (no subject doing the running).

The fix

Attach the dependent clause to a complete sentence:

When the bell rang**, the students packed up.**

Notice the comma. When the dependent clause comes first, put a comma after it. When it comes second, you usually do not need one:

The students packed up when the bell rang.

Your move

Read the words. Find the subject and the verb. Then ask: does this finish a thought, or am I left waiting? If you are left waiting, it is a fragment, and it needs to be joined to a complete sentence.

Sentence Structure: Practice

Part 2 of 2 — Fixing Run-Ons

Part 1 was about sentences with too little: fragments. This part is about sentences with too much: run-ons.

What a run-on is

A run-on happens when two complete sentences are pushed together without the right punctuation.

The power went out we lit candles.

"The power went out" is complete. "We lit candles" is complete. Nothing separates them, so the reader has no place to stop.

If a comma is doing the job all by itself, that version has a special name — a comma splice — and it is just as wrong:

The power went out, we lit candles.

Three fixes — all correct

1. Period. The power went out. We lit candles.
2. Semicolon. The power went out; we lit candles.
3. Comma + a joining word. The power went out, so we lit candles.

The joining words for fix 3 are for, and, nor, but, or, yet, so — remembered as FANBOYS.

The names for sentence types

• Simple = one independent clause. We lit candles.
• Compound = two independent clauses joined by a semicolon, or by a comma + FANBOYS. The power went out, so we lit candles.
• Complex = one independent clause plus at least one dependent clause. When the power went out, we lit candles.

Your checklist

1. Find the subject and verb in each half.
2. Can each half stand alone? If yes, they are two complete sentences.
3. Two complete sentences need a period, a semicolon, or a comma + FANBOYS.
4. A comma alone between two complete sentences is always wrong.
5. A dependent clause at the front (because, although, when, if, since) takes a comma after it.