Sentences

Is "Running fast" a sentence? What is the difference between a clause and a phrase?

A sentence is a complete unit of meaning. It must contain at least a subject (who or what) and a verb (what happens).

Understanding how sentences are built helps you avoid common problems like fragments and run-ons.

Complete sentence vs fragment

A complete sentence expresses a full idea:

The dog barked loudly.

A fragment is incomplete:

Running down the street. (missing subject)
Because it was raining. (incomplete thought)

Even if it “sounds right”, a fragment is not a full sentence.

What is a clause?

A clause is a group of words with a subject and a verb.

There are two main types:

Independent clause — can stand alone:
She studied hard.

Dependent clause — cannot stand alone:
because she studied hard

Dependent clauses need to be connected to a main clause.

What is a phrase?

A phrase is a group of words that does NOT contain both a subject and a verb.

Examples:
in the morning, very quickly, under the table

A phrase adds detail, but cannot form a sentence on its own.

Run-on sentences

A run-on sentence joins two complete sentences incorrectly.

❌ It was late we went home.

Correct versions:

✔ It was late, so we went home.
✔ It was late. We went home.

Use punctuation or conjunctions to connect ideas properly.

Types of sentences

Declarative (statement):
The sky is blue.

Interrogative (question):
Is the sky blue?

Imperative (command):
Sit down.

Exclamatory (strong feeling):
What a beautiful day!

How to recognise problems

When writing, check:

1. Does the sentence have a subject and a verb?
2. Does it express a complete idea?
3. Are clauses joined correctly?

If not, you may have a fragment or a run-on.

Key idea

A sentence is built from clauses, and clauses are built around verbs.

Understanding this structure makes your writing clearer and more controlled.