In formal spoken or written English, every sentence must be complete. The basic rule is that all sentences must have a subject (S), which can be a pronoun, a noun, or a noun phrase, and a verb (V), which can also be a verb phrase. In many cases, the verb can be followed by a direct object (O). Consider the following examples.
- She works. (S) + (V)
- Fish swim. (S) + (V)
- The children played. (S) + (V)
- The bus driver needs a break. (S) + (V) + (O)
- My mother liked the movie. (S) + (V) + (O)
Every sentence must have a subject. The imperative sentence is an exception to this basic rule, because the subject, you, is understood. Imperative sentences are used to instruct someone to do something.
- Go to class.
- Pick up your mess, please.
- Read objective newspapers.
Verbs that do not require a direct object are called intransitive verbs. Some common intransitive verbs are exist and rise. They are typically used with prepositional phrases, as illustrated in the following examples.
- It is possible that life existed on Mars millions of years ago.
- Black smoke rose from the burning tires.
The subject of a sentence can be a noun phrase, which can be simple or complex. The subject can be one word or a group of words that includes a noun together with other words that provide information about the noun. Some noun phrases can be quite complex. Consider the following sentences.
- The boy went to the playground.
- The lively boy went to the playground.
- The lively boy next door went to the playground.
No matter how complex a noun phrase is, it still remains the subject of the sentence and determines the form of the verb. The verb in the sentences above is went.
The verb in a sentence can also appear in a verb phrase.
- He has often spoken of you.
- She will not be able to understand this document.
Sometimes extra information is added before the subject and verb, or between the subject and the verb. This information is often adverbial. In the first example below, the adverbial phrases tell where, how frequently, and when the action took place. In the second example, the adverbial phrase tells why and when the action took place.
- In Pennsylvania, Marc often went running in the morning.
- Marc, because he was feeling unhealthy, went running in the morning.
In both of these examples, when we ask the question “Who went running?” the answer is “Marc”—the subject of both sentences. The added information is that he often ran in the morning when he was in Pennsylvania, and that he ran because he felt unhealthy.
There are many types of sentence modifiers. Among the most important are adjectives, adverbs, and prepositional phrases.
Adjectives modify nouns or pronouns.
- That striped snake is poisonous.
- Our new neighbor is a professional basketball player.
- He is old.
Adverbs modify verbs, adjectives, or other adverbs.
- She seldom wrote after she moved away.
- The severely wounded man was taken to the hospital.
- The witness spoke very nervously about the robbery.
Prepositional phrases can modify nouns or verbs.
- The man in the garden is a police officer.
- For many years they lived in Mexico.