Section 9.2 Clauses and Phrases
Before examining how sentences are built from multiple clauses, it helps to draw a clear line between two fundamental building blocks: clauses and phrases. You have been working with both since Chapter 5, but the difference becomes especially important now that we are studying how clauses combine.
A phrase is a word or group of words that functions as a grammatical unit but lacks a subject-predicate pair. Phrases are the components of clauses—they fill slots in the sentence, but they cannot express a complete thought on their own. You have already worked extensively with noun phrases (NP), verb phrases (VP), prepositional phrases (PP), adjective phrases (AdjP), and adverb phrases (AdvP).
A clause, by contrast, contains both a subject and a predicate. A clause can be independent (capable of standing alone as a sentence) or dependent (grammatically incomplete without a main clause to support it).
| Unit | Has subject + predicate? | Example |
|---|---|---|
| Phrase | No | the dog, ran quickly, in the park |
| Independent clause | Yes — stands alone | The dog barked. |
| Dependent clause | Yes — cannot stand alone | when the dog barked |
The key test: does the unit have both a subject and a finite verb? If yes, it is a clause. If it can stand alone as a sentence, it is an independent clause. If it begins with a subordinating word that makes it lean on another clause for completion, it is a dependent clause.
Phrases are parts of clauses—an NP fills the subject slot, a VP fills the predicate slot, a PP attaches as a modifier. The rest of this chapter is about what happens when full clauses combine. Understanding the phrase/clause distinction prevents a common confusion: a sentence with two verb phrases or two noun phrases is not automatically a compound sentence. Only when there are two full clauses—each with its own subject and predicate—does compounding apply.
