Nouns can take on two different roles in a sentence: they can be subjects or objects. Understanding subjects and objects simply means understanding who (or what) performed an action, and who (or what) was affected by that action.

Identifying Subjects

In a sentence, the subject completes the action. The subjects are italicized in the examples below:

• Mary drew a picture for her mother. 
• Lions eat many animals, such as rabbits.

The subject does not have to be a person or animal—it can also be an inanimate object: 

• The coffee let off steam. 
• The cup is on the table. 

Note that the subject includes not just the noun, but also the article (e.g., the, a, an) that goes along with it.

Identifying Objects

An object is the recipient of an action. There are two types of object: direct and indirect. 

Direct Objects

In a sentence, the direct object receives the action of the subject. See the italicized direct objects in the examples below:

• Mary drew a picture.
• The tiger chased the bunny. 

Indirect Objects

In a sentence, the indirect object answers the question "to whom or what?" or "for whom or what?" See the italicized indirect objects in the examples below.

• Mary drew a picture for her mother.
• Bill threw the ball to his sister.

Sign

In this sign saying "Do not feed the coyotes", are coyotes the subject, the object, or the indirect object? (Answer: They are the direct object.)

Identifying Indirect Objects without a Preposition

Sometimes direct object and indirect object cannot be identified by word order alone—and there is not always a "to" or "for" to make it clear: 

• The boy fed the dog a bone. 

To correctly identify the indirect object, ask yourself which part of the sentence would answer the question "to/for whom or what?" 

• "The boy fed a bone to the dog." 

Phrased this way, it becomes clear that the dog is the indirect object and the bone is the direct object.

Identifying Subject and Object in the Active Voice

If a sentence is written in the active voice, it means that the subject comes before the verb, and the object follows the verb. All of the examples above are written in the active voice. 

A simple way to identify whether a noun is a subject or an object in an active-voice sentence is to note where it is in the sentence. If the noun precedes the verb, it is the subject. If it follows the verb, it is the object. See the examples below:

• The alien landed the spaceship. (“The alien” is the subject and “the spaceship” is the direct object.) 
• Mathilda ate the sandwich. (“Mathilda” is the subject and “the sandwich” is the direct object.)

Identifying Subject and Object in the Passive Voice

In passive-voice sentences, the usual rules do not apply. Rather, we need to look at word order to find the subject and object. In a passive-voice sentence, keep in mind that the order will be subject–verb phrase–object. See the following examples.

• The sandwich was eaten by Mathilda. (“The sandwich” is the subject and “Mathilda” is the object.)
• The spaceship was steered by the alien. (“The spaceship” is the subject and “the alien” is the object.)

In the passive voice, a noun coming after the word "by" is an object, while a noun coming before a form of the verb "to be" (e.g., "was") is the subject. Note the italicized words in the examples above.

Verb Types and Objects

Not all verbs require objects. A verb that requires an object is called a transitive verb: 

• She wants cake.

Without the object "cake," the sentence is incomplete and doesn't make sense. What does she want? 

A verb that does not require an object is called an intransitive verb: 

• I slept. 

With an intransitive verb, the sentence is complete with the subject and verb alone.