Sentences and Fragments: The Differences and When to Use Each One

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This page will discuss the types of sentences, what a sentence fragment is, and when each of these is appropriate to use. You have already learned about subjects, which tells who or what is doing something, and predicates, which tell what the subject is doing. These are used to create the various patterns in sentences. We will also discuss some of the big problems with sentence construction and how to correct them.


Obviously, the basic pattern for a simple sentence is subject - predicate.

feel sleepy.
came home from college yesterday.
The children and I
went to the zoo.

Both of these components can become more complex. The predicate, for instance, can be in two parts: the verb and the complement. If you need refreshers on these, see the Parts of Speech page. You can see that none of our examples above have only a subject and a verb because very few English sentences are that simple. Thus, a more useful way to think of this pattern is subject - verb - complement.

The children and I
to the zoo.

These are simple sentences, and because they can stand alone they are also independent clauses. These are combined with other independent clauses or dependent clauses or phrases to create more complex, meaningful, interesting sentences.


The first way to think about creating more complex sentences is through coordination: using two items of equal weight within the sentence elements or by joining whole independent clauses. For instance, in the following situations, we have added more items within the three sentence elements:

Sydney and I
are cleaning
Graham's room Saturday.
to go to the store and the gas station.
called or wrote
every Christmas.

You can also do this with two independent clauses to create a very common sentence structure:

We went through the store, and Sasha met us at the back door.

Yesterday was hot, but today it is cooler.

Notice that these are joined by "and" and "but." These are called coordinating conjunctions, and the resulting sentences are called compound sentences. Here is the whole list of coordinating conjuctions:

and, or, but, for, nor, yet, so

Be aware, too that there are some adverbs which can also connect two independent clauses:

We were going to see Carmen; however, Grant got sick that day.
I have to leave right now; otherwise I will miss my plane!

Here is the list of conjunctive adverbs:

accordingly, also, anyway, besides, certainly, consequently, conversely, finally, furthermore, hence, however, incidentally, indeed, instead, likewise, meanwhile, moreover, nevertheless, next, nonetheless, otherwise, similarly, specifically, still, subsequently, then, therefore, thus

Note that some punctuation (a comma or semi-colon) is necessary to use between the two clauses to reinforce the independent nature of the clauses.

The two elements on either side of these conjunctions should both be independent clauses, so make sure that you have the full subject-predicate form on either side when you use them.

The final way to join two independent clauses without adding a word is with a semi-colon (like this); for that discussion see the Other Punctuation page.


Even more complexity of meaning can be created in sentences by using subordination, that is, by using an independent clause joined with word groups (individual words, phrases or clauses) that modify the independent clause but take a less important place in the sentence than the independent clause. Whew! These are called complex sentences; let's look at this in practice:

Peter has been distraught since Wendy left.

Although I was with you all day, I never noticed your new haircut.

Because of the bad weather, we must stay in today.

"Since Wendy left" modifies the main part of the sentence by specifying when this happened to Peter. "Although..." gives more information about my ignorance of your hairstyle. "Because..." explains why we must stay in. Notice the first two of these are clauses because they contain a subject and predicate, and the third one is a phrase because it does not. All of them are modifying subordinate elements in the sentences, however.

Also note that, as in coordination, in subordination there are specific words which start each of these dependent modifiers. Here is the list of subordinating conjunctions:

after, although, as, as if, because, before, even though, if, in order that,
rather than, since, so that, than, that, though, unless, until, when, where, whether, while

There are other adverbs which also introduce subordinate elements and indicate the relationship between the parts of the sentence:

how, what, whatever, which, whichever, who, whom, whoever, whomever, whose, why

These may also be used with phrases or clauses:

Whomever you choose, you must do it today!

Note in these situations that you only need to add a comma when the modifying element comes before the main part of the sentence.

The major thing to remember about subordination is that you are using these elements to modify the main part of the sentence, thus choose your conjunction/adverb and your structure accordingly so it achieves your desired effect.


  1. When NOT to use them.

    A sentence fragment is a group of words which is used as a sentence but does not have the subject-predicate form described above. Why are your writing instructors always telling you not to use these? The answer lies in the differences between written and spoken communication. We are always using fragments in speech, and our conversations would be pretty cumbersome if we always spoke in full sentences:

    Are you going to school today?
    Yes, I am going to school today.

    What time will the bus be picking you up?
    The bus will be picking me up at about eight o'clock.

    Even though written communication may not be as lengthy as these examples, it is still necessary for the sake of clarity and style to spell out our ideas more fully. If you are not sure if you have written a sentence or a fragment, try the following test:


    Subordinate clause fragment: Because we are leaving the next day.

    No verb fragment: The left side of the screen.

    There are two easy ways to fix unwanted sentence fragments:

    1. Hook the fragment on to the sentence nearby which it is modifying.
      Because we are leaving the next day, we want to visit the Louvre on Tuesday.

    2. Turn the fragment into a sentence by adding the missing parts.
      The left side of the screen only showed Mulder's face.

  2. When you SHOULD use them

    There are specific and limited instances when sentences fragments are effective writing. Make sure that you have one of these purposes in mind when you spot a fragment in your proofreading.

    If you are not doing one of these things, fix the fragment as directed above.


Aside from fragments, there are a couple of major errors that writers make in sentence construction. The problem with all of these is that they do not accurately depict the relationship between the two clauses, and that can cause misunderstanding for your reader. Do you see any of these in your writing?