Components of a Sentence
A complete sentence consists of a subject and a predicate.
The subject is the word or group of words that names the person, place, thing, or idea that the sentence is about, and the predicate consists of the verb and any words that are necessary to complete its meaning. Both subject and predicate are necessary for the sentence to express a complete thought.
In a way, every sentence can be compared to a story. Like a story, a sentence must be about someone or something, and that person or thing must have something said about it.
In grammatical terms, a complete sentence is an independent clause, which is a group of words that contains a subject and a predicate and can stand on its own as a complete thought.
I could not play in the basketball game.
In this sentence the subject is "I," and the rest of the sentence is the predicate.
Now consider this clause:
Because I sprained my ankle.
Here, also, the subject is "I," and there is a predicate, "sprained my ankle," but this clause is dependent (or subordinate), which means that in order to express its meaning completely it must be joined to an independent clause, as follows:
Because I sprained my ankle, I could not play in the basketball game.
As this example illustrates, a dependent (or subordinate) clause cannot stand on its own. It must be joined to an independent clause to make its meaning clear.
All complete sentences must contain at least one independent clause.
Part of a Sentence
A sentence may have more than one person, place, thing, or idea as the subject. When this occurs, the sentence has a compound subject.
The students and teachers left the building when the fire alarm sounded.
In this example, the phrase "students and teachers" is a compound subject.
A phrase is a group of words that cannot function as a clause because it lacks either a subject, a predicate, or both. A prepositional phrase is a phrase that indicates a relationship of some kind (often a relationship of space or time) between the object of the preposition and another word.
The book was found underneath the couch.
In this example, "underneath the couch" is a prepositional phrase. The object of the preposition is "couch," and the preposition, "underneath," indicates the relationship between the subject of the sentence (book) and the couch.
Common prepositions include in, on, of, under, near, by, with, and about.
Just as prepositional phrases are built on prepositions, participial phrases are built on either the past or present participle of a verb. They are used as modifiers and usually describe nouns.
The participles commonly used in English are the present participle (the -ing form of verbs) and the past participle (the -ed form of regular verbs). Thus, "walking" and "walked" are the present and past participles of the infinitive verb "to walk." A participial phrase consists of the verb participle and any modifiers that go with it.
walking over rocky ground.
In this example, "walking" is the participle and "over rocky ground" (a prepositional phrase) completes the participial phrase.
Since many participial phrases contain the participle of an action verb, students sometimes confuse a participial phrase with the main verb of a sentence. Look closely, though, and you will see that the action word in a participial phrase is never a complete verb. It is usually only a past or present participle that lacks the helping verb it would need to form a predicate.
A young man staring at his cell phone bumped into me.
The subject of this sentence is "A young man," and there may seem to be two predicates, "staring at his cell phone" and "bumped into me." One of these, however, is only a participial phrase. How can you tell which one? If you remove the first of these two phrases, you get A young man bumped into me. This is clearly a complete sentence with a verb, bumped, in the past tense.
However, if you remove the second phrase, you get A young man staring at his cell phone. Is this a complete sentence? Compare it with this:
A young man was staring at his cell phone.
Only when we add was do we have a complete sentence. Why? Because staring cannot function as a verb without the helping verb was or is. So, in our original sentence, "staring at his cell phone" is a participial phrase used to describe the young man, and the predicate is "bumped into me."
Exercise: Subjects, Prepositions, and Particical phrases
Read the following sentences.
- Circle the subject or subjects,
- underline any prepositional phrases, and
- put double lines under any participial phrases.
- The gym is open until nine o'clock tonight.
- We went to the store and bought some ice.
- The student with the most extra credit will win a homework pass.
- The pickup truck, going way too fast, skidded on the ice.
- Anita sprinted over the finish line, winning the race with time to spare.
- People working for that company were surprised about the merger.
- The soundtrack has over sixty songs in languages from around the world.
- Studying intensely, Juan earned all A's last semester.
- A dog soaked with rain shook water all over the room.
- A man offering profuse apologies was gathering parcels strewn on the floor.
- A sentence is complete when it contains both a subject and verb (predicate). A complete sentence makes sense on its own.
- Every sentence must have a subject, which usually appears at the beginning of the sentence. A subject may be a noun (a person, place, or thing) or a pronoun.
A compound subject contains more than one noun.
- A prepositional phrase describes, or modifies, another word in the sentence but cannot be the subject of a sentence.
- A verb is often an action word that indicates what the subject is doing. Verbs may be action verbs (transitive or intransitive), linking verbs, or helping verbs.
Remembering the five basic sentence patterns is useful when correcting grammar errors.
- Fragments and run-on sentences are two common errors in sentence construction.
- Fragments can be corrected by adding a missing subject or verb or combining a dependent clause with an independent clause.
- Run-on sentences can be corrected by adding appropriate punctuation or using coordination or subordination.