In addition to a subject, every sentence has a predicate, which asserts or asks something about the subject or tells the subject to do something. The key word of most predicates is a verb. The simple predicate of a sentence consists of the main verb and any auxiliaries; the complete predicate includes the simple predicate and any modifiers of the verb and any objects or complements and their modifiers.

A compound predicate contains two or more verbs that have the same subject, usually joined by a coordinating or a correlative conjunction.

Omar shut the book, put it back on the shelf, and sighed.

On the basis of how they function in predicates, verbs can be divided into three categories: linking, transitive, and intransitive.

Linking verbs

A linking verb connects a subject with a subject complement (SC), a word or word group that identifies or describes the subject.

A subject complement can be either a noun or pronoun (teacher) or an adjective (patient).

The forms of be, when used as main verbs, are common linking verbs. Other verbs, such as appear, become, feel, grow, look, make, seem, smell, and sound, can also function as linking verbs, depending on the sense of the sentence.

Transitive verbs

A transitive verb expresses action that is directed toward a noun or pronoun called the direct object (DO).

Here, the subject and verb do not express a complete thought. The direct object completes the thought by saying what he peeled.

A direct object may be followed by an object complement (OC), a word or word group that describes or identifies the direct object. Object complements may be adjectives, as in the first example below, or nouns, as in the second example.

Some transitive verbs may also be followed by an indirect object (IO), which is the recipient of the direct object. The indirect object tells to whom or what, or for whom or what, the verb does its action.

Transitive verbs typically require you to state the object explicitly. For example, you can’t just say Give! even if it is clear that you mean Give me the phone.

Intransitive verbs

An intransitive verb does not have a direct object.

The verb persevered has no object (it makes no sense to ask, persevered what?), and the verb watched is directed toward an object that is implied but not expressed.

Some verbs that express action can be only transitive or only intransitive, but most can be used either way, with or without a direct object.