You may know that the basic parts of speech come together to make a sentence. But what parts of a sentence are required to form a complete thought? Learn more about identifying parts of a sentence, which parts of a sentence are required and how they work together.
The eight parts of speech — nouns, verbs, adjectives, prepositions, pronouns, adverbs, conjunctions, and interjections — form different parts of a sentence. However, to be a complete thought, a sentence only needs a subject (a noun or pronoun) and a predicate (a verb). If you only include one of these two parts, you will have only a sentence fragment, which is grammatically incorrect.
Examples of subjects in sentences include the words seen in bold below:
- Kelly walked down the street. (Kelly is a noun)
- They went to school. (They is a pronoun)
- The black cat slept all day. (The black cat is a noun phrase)
There are a few different types of subjects. A simple subject is just one word, without any modifiers, usually a noun or pronoun. A complete subject is the simple subject plus all modifiers. A compound subject is made up of more than one subject element.
- Simple subject - Kate is a nice girl.
- Complete subject - Jeffrey's poem about his mother made the class cry.
- Compound subject - Paul and Tommy joined the soccer team at the same time.
Notice that the subject comes before the verb in each sentence (is, made, joined). No matter how long the subject is, it is always the noun performing the object.
The predicate of a sentence includes the verb and everything that follows it. This typically tells what the subject does with an action verb or describes the subject using a linking verb and a complement.
- Kelly walked down the street. (What did Kelly do?)
- They went to school. (What did they do?)
- The black cat slept all day. (What did the black cat do?)
All of these words make up the complete predicate of the sentence. The verb alone is the simple predicate. As with subjects, it's also possible to have a compound predicate that consists of two different actions.
Take a look at the examples below to note the differences:
- Simple predicate - Harry cried.
- Complete predicate - The mouse slowly ran towards the food.
- Compound predicate - She laughed at the dog's tricks and decided to adopt him.
Predicates can contain a good deal of information and may be quite long. They often have several parts in addition to the verb, including objects and complements.
Now that you know the two main parts of a sentence, take a look at how optional elements work. These elements include objects, complements and modifiers.
- Susan bought the gift. (What did Susan buy?)
- He wrote a letter. (What he write?)
- The boy threw the ball. (What did the boy throw?)
Indirect objects include more information about the person or thing towards which the action is directed. They answer the questions that begin with who.
- Susan bought him the gift. (Who did Susan buy the gift for?)
- He wrote me a long letter. (Who did he write a letter to?)
- The boy threw his mother the ball. (Who did he throw the ball to?)
You can also rephrase these sentences so that the indirect object appears after the direct object in a prepositional phrase. For example, "Susan bought the gift for him" is also a correct way to state the sentence.
In predicates that use linking verbs rather than action verbs, nouns following the verb are known as complements. Complements can be nouns, noun phrases, pronouns, or adjectives. Subject complements, also known as predicate nominatives, modify the subject by describing it further.
- I am a mother.
- The cat was the laziest creature.
- The woman is blonde.
Object complements function the same way, but for the object of the sentence instead. They follow transitive verbs, which express action performed toward an object.
- I named my son Carson. (The noun Carson complements the object son)
- The cat considers me his servant. (The noun phrase his servant complements the object me)
- The woman dyed her hair blonde. (The adjective blonde complements the object her hair)
These complements help to explain more in a sentence. You can see how they fit into a sentence when you practice sentence diagramming.
Like complements, modifiers add additional information. Adjectival modifiers modify nouns and pronouns, while adverbial modifiers modify verbs, adjectives, and other adverbs. It is possible for parts of speech to do this work alone in the sentence in either the subject or the predicate.
- The blue boat sank. (The adjectival modifier blue modifies the subject boat)
- The boat slowly sank. (The adverbial modifier slowly modifies the verb sank)
Not all modifiers are single words. Sometimes they are groups of words, known as phrases, that work together.
- She exercised in the morning.
- The boy fell asleep at school.
- They bought a very expensive house.
Modifiers are optional when it comes to writing sentences. They merely give additional information and are not required the way a subject and verb are. Note that complements are considered to be a type of modifier as well, but they are more important to the meaning of a sentence.
In your writing, knowing that each sentence requires a subject and a verb will help ensure that you write grammatically complete sentences. Using complements, adverbials and other modifiers will add interest. Just be sure not to use too many in the same sentence to avoid confusing run-on sentences.