The Parts of a Sentence

Verb

The main verb, or verb phrase, of a sentence is a word or words that express an action, event, or a state of existence. It sets up a relationship between the subject and the rest of the sentence.

• The first high-level language to be widely accepted, FORTRAN, was implemented on an IBM 704 computer.
• Instruction in the source program must be translated into machine language. (passive construction)
• The operating system controls the translation of the source program and carries out supervisory functions. (compound verb)

Predicate

The predicate is the rest of the sentence coming after the subject. It can include the main verb, subject complement, direct object, indirect object, and object complement.

• The pressure in a pressurized water reactor varies from system to system.
• The pressure is maintained at about 2250 pounds per square inch to prevent steam from forming.
• In contrast, a boiling water reactor operates at constant pressure.

Subject Complement 

The subject complement is that noun, pronoun, adjective, phrase, or clause that comes after a linking verb (some form of the be verb).

• The maximum allowable concentration is ten parts H2S per million parts breathable air.
• The deadening of the sense of smell caused by H2S is the result of the effects of H2S on the olfactory nerves of the brain.
• Continuous exposure to toxic concentrations of H2S can be fatal.

Direct Object

A direct object—a noun, pronoun, phrase, or clause acting as a noun—takes the action of the main verb (e.g., the verb is happening to the object). A direct object can be identified by putting what?, which?, or whom? in its place.

The direct objects appear in bold text in the examples below:

• The housing assembly of a mechanical pencil contains the mechanical workings of the pencil.
• Lavoisier used curved glass discs fastened together at their rims, with wine filling the space between, to focus the sun’s rays to attain temperatures of 3000° F.
• The dust and smoke lofted into the air by nuclear explosions might cool the earth’s atmosphere some number of degrees.
• A 20 percent fluctuation in average global temperature could reduce biological activity, shift weather patterns, and ruin agriculture. (compound direct object)

Indirect Object

An indirect object—a noun, pronoun, phrase, or clause acting as a noun—receives the action expressed in the sentence. It can be identified by inserting to or for.

• The company is designing senior citizens a new walkway to the park area.
  • The company is not designing new models of senior citizens; they are designing a new walkway for senior citizens. Thus, senior citizens is the indirect object of this sentence.
• Please send the personnel office a resume so we can further review your candidacy.
  • You are not being asked to send the office somewhere; you’re being asked to send a resume to the office. Thus, the personnel office is the indirect object of this sentence.

Note: Objects can belong to any verb in a sentence, even if the verbs aren’t in the main clause. For example, let’s look at the sentence “When you give your teacher your assignment, be sure to include your name and your class number.”

• Your teacher is the indirect object of the verb give.
• Your assignment is the direct object of the verb give.
• Your name and your class number are the direct objects of the verb include.

Object Complement

 An object complement—a noun or adjective coming after a direct object—adds detail to the direct object. To identify object complements, insert [to be] between the direct object and object complement.

• The superviser found the program [to be] faulty.
• The company considers the new computer [to be] a major breakthrough.
• Most people think the space shuttle [to be] a major step in space exploration.

Phrases and Clauses

Phrases and clauses are groups of words that act as a unit and perform a single function within a sentence. A phrase may have a partial subject or verb but not both; a dependent clause has both a subject and a verb (but is not a complete sentence). Here are a few examples (not all phrases are highlighted because some are embedded in others):

There are two types of clauses: dependent and independent. A dependent clauses is dependent on something else: it cannot stand on its own. An independent clause, on the other hand, is free to stand by itself.

So how can you tell if a clause is dependent or independent? Let’s take a look at few of the clauses from the table above:

• when two oppositely charged bodies are brought close to one another
• Since the frequency is the speed of sound divided by the wavelength
• which, if current plans hold, will bring nuclear capacity to about 22% of all electrical capacity by 1995

These are all dependent clauses. Any clause with a subordinating conjunctions (like when or since) is a dependent clause. For example “I was a little girl in 1995” is an independent clause, but “Because I was a little girl in 1995” is a dependent clause. Clauses that start with relative pronouns, like which, also become dependent clauses.