Sentence structure refers to the way we compose sentences: how we string subjects, verbs, objects, and modifiers together in clauses and phrases. Awkward or incorrect placement of phrases and clauses can result in sentences that are confusing or unclear, or say things that you don't mean. Sentence structure is also important to style. If sentence structure is too simple or repetitive, the writing becomes monotonous for the reader. (Sentence variety will be addressed in the review for Part II.)
Subjects, Predicates, and Objects
When we write, we express our ideas in sentences. But what is a sentence, anyway?
The sentence is our basic unit of written expression. It consists of two essential parts—a subject and apredicate—and it must express a complete thought. The subject of a sentence tells us who or what the sentence is about—who or what is performing the action of the sentence. The predicate tells us something about the subject—what the subject is or does. Thus, in the following sentence:
The phone is ringing.
The word phone is the subject. It tells us what the sentence is about—who or what performs the action of the sentence. The verb phrase is ringing is the predicate. It tells us the action performed by (or information about) the subject.
The subject of a sentence can be singular or compound (plural):
I slept all day. singular subject Kendrick and I worked all night. compound subject (two subjects performing the action)
The predicate can also be singular or compound:
I bought a present. singular predicate I bought a present and wrapped it beautifully. compound predicate (two actions performed by the subject)
In many sentences, someone or something "receives" the action expressed in the predicate. This person or thing is called the direct object. In the following sentences, the subject and predicate are separated by a slash (/) and the direct object is underlined:
I / bought a present. (The present receives the action of being bought.)
Jane / loves ice cream. (Ice cream receives the action of being loved by Jane.)
Sentences can also have an indirect object: a person or thing who "receives" the direct object. In the following sentences, the direct object is underlined and the indirect object is in bold:
I / gave Sunil a present. (Sunil receives the present; the present receives the action of being given.)
The reporter / asked the president a question.
(The president receives the question; the question receives the action of being asked.)
Independent and Dependent Clauses
A clause contains a subject and a predicate and may also have direct and indirect objects. An independent clause expresses a complete thought; it can stand on its own as a sentence. A dependent clause, on the other hand, cannot stand alone because it expresses an incomplete idea. When a dependent clause stands alone, the result is a sentence fragment.
Independent clause: She was excited.
Dependent clause: Because she was excited.
Notice that the dependent clause is incomplete; it needs an additional thought to make a complete sentence, such as:
She spoke very quickly because she was excited.
The independent clause, however, can stand alone. It is a complete thought.
Subordinating Conjunctions
What makes a dependent clause dependent is a subordinating conjunction such as the word because. Subordinating conjunctions connect clauses and help show the relationship between those clauses. Here is a list of the most common subordinating conjunctions:
When a clause begins with a subordinating conjunction, it is dependent. It must be connected to an independent clause to become a complete thought:
I never knew true happiness independent clause until I met you. dependent clause
After Johnson quit, dependent clause I had to work overtime. independent clause
A sentence with both a dependent clause (DC) and independent clause (IC) is called a complex sentence. Both of the previous sentences are complex sentences.
Conjunctive Adverbs
A very common grammar mistake is to think that words such as however and therefore are subordinating conjunctions. However and therefore belong to a group of words called conjunctive adverbs. These words also signal relationships between parts of a sentence. When they are used with a semicolon, they can combine independent clauses.
Here are some examples:
I didn't go to the party; instead, I stayed home and watched a good film.
Samantha is a fabulous cook; indeed, she may even be better than Jacque.
I need to pay this bill immediately. Otherwise, my phone service will be cut off.
Compound Sentences and Coordinating Conjunctions
When two independent clauses are combined, the result is a compound sentence like the following: He was late, so he lost the account.
The most common way to join two independent clauses is with a comma and a coordinating conjunction: and, but, or, nor, for, so, yet. Independent clauses can also be joined with a semicolon if the ideas in the sentences are closely related.
I am tall, and he is short.
[IC, coordinating conjunction + IC]
I was late, yet I still got the account.
[IC, coordinating conjunction + IC]
Sentence Boundaries
Expressing complete ideas and clearly indicating where sentences begin and end are essential to effective writing. Two of the most common grammatical errors with sentence boundaries are fragments and run-ons.
Incomplete Sentences (Fragments)
As we stated earlier, a complete sentence must (1) have both a subject (who or what performs the action) and a verb (a state of being or an action), and (2) express a complete thought. If you don't complete a thought, or if you are missing a subject or verb (or both), then you have an incomplete sentence (also called a sentence fragment). To correct a fragment, add the missing subject or verb or otherwise change the sentence to complete the thought.
Incomplete: Which is simply not true. [No subject. (Which is not a subject.)]
Complete: That is simply not true.
Incomplete: For example, the French Revolution. [No verb.]
Complete: The best example is the French Revolution.
Incomplete: Even though the polar icecaps are melting. [Subject and verb, but not a complete thought.]
Complete: Some people still don't believe in global warming even though the polar icecaps are melting.
Run-on Sentences
A run-on sentence occurs when one sentence "runs" right into the next without proper punctuation between them. Usually, there's either no punctuation at all or just a comma between the two thoughts. But commas alone are not strong enough to separate two complete ideas. Here are some examples of run-ons:
Let's go it's getting late.
Whether or not you believe me it's true, I didn't lie to you.
There are five ways to correct run-on sentences:
- With a period
- With a comma and a coordinating conjunction: and, or, nor, for, so, but, yet
- With a semicolon
- With a dash
- With a subordinating conjunction to create a dependent clause: although, because, during, while, etc.
Here's a run-on sentence corrected with each of these techniques:
Parts of Speech: A Brief Review
A word's function and form is determined by its part of speech. The word calm, for example, can be either a verb (calm down) or an adjective (a calm afternoon); it changes to calmly when it is an adverb (they discussed the matter calmly). Be sure you know the different parts of speech and the job each part of speech performs in a sentence. The table offers a quick reference guide for the main parts of speech.
Phrases and Modifiers
Sentences are often "filled out" by phrases and modifiers. Phrases are groups of words that do not have both a subject and predicate; they might have either a subject or a verb, but not both, and sometimes neither. Modifiers are words and phrases that qualify or describe people, places, things, and actions. The most common phrases are prepositional phrases,which consist of a preposition and a noun or pronoun (e.g., in the attic).Modifiers include adjectives (e.g., slow, blue, excellent) and adverbs (e.g., cheerfully, suspiciously). In the following examples, the prepositional phrases are underlined and the modifiers are in bold:
He was very late for an important meeting with a new client.
He brazenly took her wallet from her purse when she got up from the table to go to the ladies' room.
Placement of Modifiers
As a general rule, words, phrases, or clauses that describe nouns and pronouns should be as close as possible to the words they describe. The relaxing music, for example, is better (clearer, more concise and precise) than the music that is relaxing. In the first sentence, the modifier relaxing is right next to the word it modifies (music).
When modifiers are not next to the words they describe, you not only often use extra words, but you might also end up with a misplaced or dangling modifier and a sentence that means something other than what was intended. This is especially true of phrases and clauses that work as modifiers. Take a look at the following sentence, for example:
Racing to the car, I watched him trip and drop his bag.
Who was racing to the car? Because the modifier racing to the car is next to I, the sentence says that I was doing the racing. But the verb watched indicates that he was the one racing to the car. Here are two corrected versions:
I watched as he raced to the car and dropped his bag.
I watched as, racing to the car, he dropped his bag.
In the first sentence, the phrase racing to the car has been revised to raced to the car and given the appropriate subject, he. In the second sentence, racing to the car is right next to the modified element (he).
Here's another example:
Growling ferociously, I watched as the lions approached each other.
It's quite obvious that it was the lions, not the speaker, that were growling ferociously. But because the modifier (growling ferociously) isn't right next to what it modifies (the lions), the sentence actually says that I was growling ferociously. Here's the corrected version:
I watched as the lions, growling ferociously, approached each other.
Again, the sentence is clearer now because the modifier is right next to what it modifies.
Sometimes these errors can be corrected simply by moving the modifier to the right place (next to what it modifies). Other times, you may need to add a subject and verb to clarify who or what is modified by the phrase. Here are some more examples of misplaced and dangling modifiers and their corrections:
Incorrect: Worn and tattered, Uncle Joe took down the flag.
Correct: Uncle Joe took down the flag, which was worn and tattered. OR Uncle Joe took down the worn, tattered flag.
Incorrect: While making breakfast, the smoke alarm went off and woke the baby.
Correct: While I was making breakfast, the smoke alarm went off and woke the baby. OR
The smoke alarm went off and woke the baby while I was making breakfast.
Parallel Structure
Parallel structure is an important part of effective writing. It means that words and phrases in the sentence follow the same grammatical pattern. This makes ideas easier to follow and expresses ideas more gracefully. Notice how parallelism works in the following examples:
Not parallel: We came, we saw, and it was conquered by us.
(The first two clauses use the active we + past tense verb construction; the third uses a passive structure with a prepositional phrase.)
Parallel: We came, we saw, we conquered.
(All three clauses start with we and use a past tense verb.)
Not parallel: Please be sure to throw out your trash, place your silverware in the bin, and your tray should go on the counter.
(Two verbs follow the to + verb + your + noun pattern; the third puts the noun first, then the verb.)
Parallel: Please be sure to throw out your trash, place your silverware in the bin, and put your tray on the counter.
(All three items follow the to + verb + your + noun [+ prepositional phrase] pattern.)
Parallelism is most often needed in lists, as in the previous examples, and in the not only/but also sentence pattern.
Hermione's nervousness was exacerbated not only by the large crowd, but also by the bright lights.
(Each phrase has a preposition, an adjective, and a noun.)
Their idea was not only the most original; it was also the most practical.
(Each phrase uses the superlative form of an adjective.)
Active and Passive Voice
In most cases, effective writing will use the active voice as much as possible. In an active sentence, the subject performs the action:
James filed the papers yesterday.
Jin Lee sang the song beautifully.
In a passive sentence, on the other hand, the subject is passive.Rather than performing the action, the subject is acted upon:
The papers were filed by James yesterday.
The song was sung beautifully by Jin Lee.
Active sentences are more direct, powerful, and clear. They often use fewer words and have less room for confusion. There are times when the passive voice is preferred, such as when the source of the action is not known or when the writer wants to emphasize the recipient of the action rather than the performer of the action:
Protective gear must be worn by everyone entering this building.
As a general rule, however, sentences should be active whenever possible.
June Workbooks Are Here!
Get Active! 9 Games to Keep Kids Moving 
Are Cell Phones Dangerous for Kids?
