Online College Courses for Credit

Grammar Basics -- Sentence Structure

Grammar Basics -- Sentence Structure


To review the identification and definition of sentences: complete sentence, and independent and dependent clauses. It also defines and gives examples of sentence fragments, subjects, predicates, and phrases.

This lesson defines and exemplifies sentences and phrases on the base level only. It does not cover the many types of phrases or the complicated sentence structures that exist. But it should be crystal clear what a phrase, clause, and sentence are when you have finished.

See More
Fast, Free College Credit

Developing Effective Teams

Let's Ride
*No strings attached. This college course is 100% free and is worth 1 semester credit.

38 Sophia partners guarantee credit transfer.

299 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 33 of Sophia’s online courses. Many different colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.


The Hierarchy

I'm Going To Make This Really Simple:

The four grammatical units -- word, phrase, clause, and sentence -- constitute a hierarchy. The word is the lowest on the hierarchy, while the sentence is the highest. Think of it like a reverse pyramid, with Word, the smallest piece, on the bottom.

A Phrase contains one or more Words.

A Clause contains one or more Phrases.

A Sentence contains one or more Clauses.

Source: The Oxford English Grammar, by Sidney Greenbaum, 1st Ed.

Phrase / Clause / Sentence Defined

A phrase has no subject or verb together. But it does have a main word. And this main word may be a noun or verb. The sentence below has four phrases:

"The title of the course was Woodland Ecology."

The title / of the course / was / Woodland Ecology = noun phrase / prepositional phrase / verb phrase / noun phrase

A clause has a subject and verb.

sentence is one or more clauses that make(s) sense on its (their) own. Sentence types are simple, compound, complex, and compound complex.

Clauses may be either independent or dependent. Two independent clauses are connected by a coordinating conjunction, and form a "compound" sentence. A dependent clause must have an independent clause that it depends on to make sense. The two are joined by a subordinating conjunction, and form a "complex" sentence.

SIMPLE: The title of the course was Woodland Ecology = single independent clause.

COMPOUND: The title of the course was Woodland Ecology, / and / I took it for a full semester = independent clause / coordinating conjunction / independent clause.

COMPLEX: Despite / my not having the prerequisites, / I took the Woodland Ecology course  =  subordinating conjunction / dependent clause / independent clause

COMPOUND-COMPLEX: Despite / my not having the prerequisites, / I took the Woodland Ecology course, / and / I passed with flying colors = subordinating conjunction / dependent clause / coordinating conjunction / independent clause.

Source: The Oxford English Grammar, by Sidney Greenbaum, 1st Ed.


A school teacher describes what a clause is.

Source: YouTube


Sentence fragments are not sentences.  

Let me repeat that:


A fragment doesn't have a subject and a verb, therefore it has no complete, stand-alone thought. 

EX: "I met him on the first half of the flight. From New York to Chicago."

"From New York to Chicago" has neither a subject nor a verb; therefore, it's a fragment, and it obviously can't stand alone. So it's not a sentence, simple or otherwise. The fragmented part does make sense with the other part, though, so we don't have to burn it.  Instead, let's join them:

"I met him on the first half of the flight, from New York to Chicago."

EX #2: "He was an interesting talker. But not to me."  

"But not to me" doesn't have a subject or a verb, so it doesn't make any sense alone. It's a fragment.  We could join them like we did the first one, OR -- and better -- we could make it one sentence:

I didn't think he was an interesting talker.

Source: The Elements of Style by Strunk & White, 3d Ed., and the Oxford English Grammar, by Sidney Greenbaum 1st Ed.


A sentence consists of a subject and a predicate. Simple subjects are nouns or pronouns; simple predicates are verbs. The subject may consist of only one word (noun or pronoun). The predicate also may consist of only one word (verb). A sentence consisting of a one-word (main) subject and a one-word (main) predicate is an independent clause, and is also a sentence in its simplest, bare-bones form. 

Examples: (Subjects are blue, verbs are red, all modifiers) 

Judy ran.   Teddy barked.   He tripped.   Birds fly.   All these are simple sentences; that is, they each consist of one independent clause. All predicates have a verb. In sentences as basic as these, the verbs are the predicates.

Most sentences, though, have more than just the subject and verb. The extra words expand on the thought of the subject or verb, but the base of the sentence is still the simple (or main) subject and simple (or main) predicate. 

Judy ran to her piano lesson.   Teddy barked at the deer.   He tripped over the rake.   Some birds fly south for the winter.  

No matter how  many words the sentence has, it MUST have an independent clause, the basic point of the sentence.  Example:

Despite the fact that she had thirty minutes before her piano lesson, Judy ran all the way from her home because she wanted to practice beforehand.

"Judy ran" is the noun subject and the verb, and those alone make up the simple sentence, the independent clause.

But there are other words in that sentence which expand on the noun and verb, and they make up the whole, or complete, subject and the complete predicate. They make the sentence more colorful, more interesting, etc. The complete subject is "Despite the fact that she had thirty minutes before her piano lesson, Judy," and the complete predicate is "ran all the way from her home because she wanted to practice beforehand."  These additions create a better picture, but they also make a more complicated sentence. But the simple sentence, "Judy ran," is still there, and must be there!

Sometimes, the simple subject and the simple verb are split up in the sentence, but they are still in the sentence, and still make up an independent clause.

Example: Judy, despite its making her a half hour early, ran all the way to her piano lesson because she wanted to practice beforehand.

Both "Judy" and "ran" are still there, and the thought of the sentence is still there, but it's been rearranged to make the writing more interesting. In writing anything of length, you want to mix up your sentence styles so you don't put your reader to sleep.

Source: The Oxford English Grammar, by Sidney Greenbaum, 1st Ed.