A sentence is a group of words (sometimes, just one word) that forms a complete idea.

A sentence is formed by parts that function in relation to one another. The two basic parts are the subject and the predicate.

The subject of a sentence is often who or what performs the action of the verb.

It can also be on whom or what an action is performed.

Sometimes the subject is merely in the condition indicated by the verb.

The subject is not always found at the beginning of the sentence.

It can even be after the verb.

The grammatical subject is not always what the sentence is about.

Two or more subjects joined by and form a compound subject.

A predicate can be a verb alone.

It can also be a verb and other components.

Two or more verbs governed by the same subject and joined by and are compound verbs.

A verb phrase contains a verb in the form of a participle. A participle is a form of a verb that ends in ‑ing or ‑ed. Verb phrases work as adjectives or nouns.

In the first sentence above, terrified is the participial form of the verb terrify. The phrase terrified by the rolling boulder is an adjective that describes the hikers. In the second sentence above, the verb phrase chasing the cat is a noun.

Verb phrases are often misplaced when used as adjectives. They should be placed next to the thing they describe. In the following sentence, the verb phrase is misplaced:

In the sentence above, the recommendations are the things that are based on the evidence, but the phrase based on the evidence is placed next to we, mistakenly describing it instead. The sentence could be revised to correctly place the verb phrase:

Some participles have morphed into other parts of speech, and so verb phrases using these participles do not work as adjectives and do not describe anything:

In the sentence above, provided is the participial form of provide, but the phrase provided that they read the text works here as a conjunction. The word provided is not intended to describe anything in the sentence; thus, it is fine to place provided that they read the text next to the students.

A complement is a word or phrase that is essential to the meaning of the sentence.

Notice that without the complements the meaning of the sentences would be incomplete.

Complements can be phrases or clauses:

More than one complement joined by and is called a compound complement.

A sentence may have a direct object.

A direct object is a noun, pronoun, phrase, or clause that receives the action of the verb and answers the question What? or Whom?

A sentence may also have an indirect object. An indirect object is a noun, pronoun, phrase, or clause that receives the direct object or its effect and answers the question To what? or To whom?

Two objects joined by and are called compound objects. Compound objects can be either direct or indirect.

A sentence can have compound direct objects.

It can have compound indirect objects.

It can have compound direct and indirect objects.

Sentences can also have a retained object.

In a sentence such as The celebrity sent Antonio a text message, if you make the indirect object (Antonio) the subject of the sentence, Antonio was sent, the verb (was sent) retains the direct object (a text message):

A text message is the retained object.

A clause is a group of words that contains a subject and a verb. A phrase is a group of words that lacks a subject-verb unit but otherwise functions together.

When a clause makes a complete sentence, such as The umbrella suddenly broke, it is called an independent clause. A clause that does not make a complete sentence is called a dependent clause (or subordinate clause). All sentences have at least one independent clause, which is sometimes called the main clause. Dependent clauses can be combined with independent clauses to form sentences.

An independent clause can be followed by a dependent clause.

A dependent clause can precede an independent clause.

A modifier is a word or group of words that describes—that is, modifies—another part of the sentence. Modifiers answer questions like What kind? Where? Why? When? How? and In what manner? Modifiers can add color or energy to a sentence, but unlike nouns and verbs, they are not needed to make a sentence complete.

Some modifiers modify subjects or objects. They describe the subject or object of a sentence, telling us what kind of person, place, thing, or idea it is.

Here, “red” modifies the subject, “robin,” telling us what kind of robin found the worm.

The phrase “in a top hat” modifies the subject, “man,” telling us what kind of man entered the room.

The clause “who grew up speaking more than one language” modifies the object, “people,” telling us what kind of people Brian envied.

Some modifiers modify predicates. They describe where, why, when, how, or in what manner something happened.

Here, the word “quickly” modifies the predicate, “filled their carts.” It tells us in what manner the shoppers filled their carts.

The phrase “to the bus stop” modifies the predicate, “ran.” It tells us where Fatima ran.

The clause “so that he wouldn’t be recognized” modifies the predicate, “wore sunglasses.” It tells us why the actor wore sunglasses.

The phrase “by disguising herself as a guard” modifies the predicate, “escaped.” It tells us how the prisoner escaped.

Some modifiers modify other modifiers. They make the modifier they describe more specific.

The modifier “very” describes another modifier, “happy,” telling us how happy the students were.

The modifier “bright” describes another modifier, “blue,” telling us what kind of blue the dog’s eyes are.

The modifier “most” describes another modifier, “amazing,” telling us how amazing the grandfather’s stories are.

Modifiers can also modify a whole sentence.

Here, the modifier, “unfortunately,” describes the entire sentence. It does not describe just the subject, “baker,” or just the verb, “lost,” or just the object, “recipe.” Rather, it describes the situation that all three parts of the sentence combine to convey.

And, of course, a single sentence can combine any or all kinds of modifiers—those that modify the whole sentence, those that modify subjects or objects, those that modify predicates, and those that modify other modifiers.

Modifiers can be restrictive or nonrestrictive. A restrictive modifier restricts, or limits, the meaning of the modified element. A nonrestrictive modifier gives supplemental information about the modified element without restricting its meaning.

In the above sentence, the modifier who lives in Chicago restricts the meaning of friend. Which friend? The one who lives in Chicago.

In the above sentence, the modifying clause, who lives in Chicago, does not restrict the identity of the modified element, dearest friend, but gives more information about the friend—namely, that the friend lives in Chicago. The modifier is nonrestrictive.

You can test to see if a modifier is restrictive or nonrestrictive by temporarily removing it and checking the resulting sentence for sense and meaning. A nonrestrictive modifier can be removed without fundamentally affecting the identity of the element it modifies, because the information it provides is supplemental. In the second sentence above, removing the nonrestrictive modifier results in the sentence My dearest friend says that the city’s museums are among the best. The identity of the modified element, my dearest friend, is not affected. In the first sentence, however, removing the restrictive modifier results in the sentence My friend says that the city’s museums are among the best. We have lost information that helps identify which friend is being referred to.

Use commas around nonrestrictive modifiers. Do not use commas around restrictive modifiers.

What happens to the meaning of the second sentence if you put commas around the modifier The Starry Night?

With commas, the modifier becomes nonrestrictive, and the sentence reads as though Van Gogh painted only one painting, which, of course, is not true. The point is that punctuation can change restriction to nonrestriction and vice versa and therefore can change the meaning of a sentence.

There are four types of sentences: simple, compound, complex, and compound-complex. A sentence contains one or more clauses, and you can classify a sentence as one of the four types by assessing the number and types of clauses it contains.

A simple sentence contains a single independent clause—that is, a subject and a predicate that form a complete thought:

A simple sentence can contain more than one verb:

A simple sentence is not necessarily a short one. Take the following example:

The subject of the sentence is still the girl. The predicate is bought a cup of lemonade and took it to the park. The part of the sentence between the dashes modifies the girl.

A compound sentence contains two or more independent clauses joined by a coordinating conjunction (and, but, yet, for, or, nor, or so), a conjunctive adverb (e.g., however, furthermore, likewise, rather, therefore), or a semicolon:

A complex sentence contains one or more dependent clauses attached to an independent clause. The dependent clauses are connected to the independent clause through subordinating conjunctions (e.g., because, after, when) or relative pronouns (who, which, that).

Note that in the last example, the dependent clause who had a freckled face and wore a striped shirt, interrupts the independent clause The girl was knocked over by a large dog.

A compound-complex sentence contains one or more dependent clauses attached to one or more independent clauses.

A verb is a word or phrase that indicates action or existence. An action can be described as occurring in the past, present, or future.

A verb may be the entire predicate (I am) or part of the predicate (He thinks it over).

A verb that performs its action on an object is transitive.

A verb that does not take an object is intransitive.

Some verbs can be either transitive (She ate her sandwich) or intransitive (She ate). Other verbs are usually transitive or usually intransitive.

A verb can be in either the active or the passive voice, depending on whether its subject does the action of the verb or is acted on. The following examples show verbs in the active voice:

In the second example, sculptor is the subject of the sentence and performs the action of the verb shapes. Notice how the form of this verb changes when it is in the passive voice:

Clay is now the subject and is being acted on by the verb.

Nouns are words that refer to persons, places, things, feelings, or characteristics. They can be divided into two main categories: common nouns and proper nouns. Common nouns are nouns that do not refer to a specific person, place, or thing, and they are not capitalized.

Common nouns can be categorized as concrete, abstract, or collective. Concrete nouns refer to tangible things that can be physically perceived. Abstract nouns refer to nonphysical things, such as ideas, characteristics, and feelings. Collective nouns refer to groups of things.

In the first sentence above, school is a concrete noun, and brilliance is an abstract noun. In the second sentence, audience is a collective noun.

Proper nouns refer to a specific person, place, or thing (e.g., names of people, cities, and months), and they are capitalized.

Nouns can act as the subject, object, indirect object, or complement of a verb. They can also function as the object of a preposition.

In the first sentence above, Miguel is the subject, and cake is the object of bought. In the second sentence, Samia is the subject and me is the indirect object—the person to whom the present was offered. In the third sentence, friends is a complement. In the fourth sentence, window is the object of the preposition through.

If a phrase in a sentence functions as a noun, it is called a noun phrase. If a clause in a sentence functions as a noun, it is called a noun clause. A noun phrase does not include a subject and verb, but a noun clause does.

In the sentence above, the new stadium is a noun phrase and is acting as the subject, and where the event is taking place is a noun clause and is acting as the complement.

A pronoun functions as a stand-in for a noun. Like nouns, pronouns refer to people, places, things, feelings, or qualities but without explicitly naming them. For instance:

Here, the pronoun she refers to the noun Barbara.

There are four main types of pronouns: personal, relative, demonstrative, and indefinite.

Personal pronouns are used to refer to yourself (I, me, we, us), to those you are speaking with (you), or to whomever or whatever you are discussing (he, she, it, him, her, it, they, them):

Personal pronouns also take on possessive forms (e.g., my, mine; your, yours; her, hers; his; their, theirs):

Relative pronouns also refer to nouns. However, they appear in the part of a sentence known as a relative clause, which modifies other elements of a sentence. The three principal relative pronouns are who, which, and that. Of these three, only who varies in form (who, whose, and whom):

Like relative pronouns, demonstrative pronouns are also dependent on their antecedents—that is, what they refer back to. They too point to earlier words but without introducing a clause. Demonstrative pronouns include this and that (together with their plural forms these and those). In writing, it is important that a demonstrative pronoun refer clearly to a particular word or words. For example:

Unlike other types of pronouns, indefinite pronouns do not require antecedents. They include words such as anything, everyone, none, nobody, neither, somebody, something, each, and either.

Adjectives are words or groups of words that modify—that is, describe—nouns and pronouns.

In this sentence, huge and loud are adjectives because they describe the nouns crowd and voice.

Various kinds of other words—including infinitives (the “to” forms of verbs), participles (the ‑ing or ‑ed forms of verbs), and nouns—can function as adjectives.

While opera, increasing, and to provide are different parts of speech—opera is a noun, increasing is a participle, and to provide is an infinitive—they all function as adjectives in this sentence because they all modify nouns. Opera modifies singer, increasing modifies lengths, and to provide modifies island.

Adverbs are words or groups of words that primarily modify verbs, as well as other modifiers and sometimes entire sentences. They usually answer the questions How? Where? When? Why? or To what extent?

Both adverbs in this sentence, frantically and before school, modify the verb cleaned. They describe how (frantically) and when (before school) Keisha cleaned her room.

Here, the adverb completely modifies the verb failed, and the adverbs safely and on a golf course modify the verb landed. These adverbs tell us to what extent (completely) the engine failed and how (safely) and where (on a golf course) the pilot landed her plane.

In this sentence, the adverbs too and notoriously do not modify verbs. Instead, they modify other modifiers. Too modifies the adjective tired, and notoriously modifies the adjective long.

Here, luckily does not modify any single word or part of speech. Rather, it modifies the whole sentence. What is lucky is the complete circumstance described by the sentence—the fact that Veena decided to bring an umbrella to work.

Finally, a sentence can contain any possible combination of adjectives and adverbs.

In this sentence, the adverb in fact describes the whole sentence, the adverb so modifies the adjective difficult, and the adverbs profusely and while they were taking it describe the verb began to sweat. The adjectives math and difficult modify test, and the adjective some modifies students.

Adjective phrases and adjective clauses are groups of words that modify, or describe, a noun or pronoun. Adjective phrases, like all phrases, do not include a subject and verb.

In the sentence above, above the mantelpiece is an adjective phrase because it describes the location of the noun, painting, and does not include a subject or verb.

Adjective clauses, like all clauses, include a subject and verb.

In the sentence above, that Mary bought last week is an adjective clause because it describes the noun blender and includes a subject, Mary, and a verb, bought.

A preposition forms a phrase with a noun or pronoun, called the preposition’s object. The preposition links the object to another word or element in the sentence. A prepositional phrase usually functions as an adjective or adverb, modifying a noun, pronoun, verb, adjective, or adverb.

In most cases a prepositional phrase functions as a unit.

Above, the preposition under forms the prepositional phrase under the bed.

In the sentence above, the preposition before forms the prepositional phrase before midnight.

Above, the preposition to forms the prepositional phrase to her.

Despite what you may have heard, it is perfectly acceptable to end a clause or sentence with a preposition. Keeping prepositions at the end of clauses usually sounds more natural and less formal because it follows spoken English.

A conjunction joins two or more parts of a sentence and expresses how the parts are related. There are two main types of conjunctions: coordinating and subordinating.

The principal coordinating conjunctions are and, but, for, nor, and or. They join sentence elements that have equal weight and the same grammatical character. They can connect words or entire phrases and clauses.

In the sentence above, and joins the words for the breakfast items. It also shows how they are related. John had all three things for breakfast, not merely one or two of them.

In the sentence above, but joins two independent clauses and shows how they relate to each other. Here but means “on the contrary” or “notwithstanding.” The fact that the train had to make extra stops might have made Ming late. He got to work on time despite the delay.

Sometimes coordinating conjunctions are preceded by correlatives. Examples are both . . . and, neither . . . nor, and not only . . . but also. These correlative conjunctions heighten the parallelism of the units that they join. The units joined should be in the same grammatical form.

In the sentence above, the correlative conjunction both . . . and joins two verb phrases that are in the same form.

Subordinating conjunctions, unlike coordinating ones, do not join words or phrases that have equal weight. They often introduce adverbial clauses that modify or qualify the main clause or the main verb of the sentence.

In the sentence above, the phrase ran out of gas works as an adverb modifying the verb drove, and until is the subordinating conjunction. Other common subordinating conjunctions are after, although, as, as if, as long as, because, before, since, so that, and while.

Some words that work as subordinating conjunctions can also be prepositions. But prepositions always introduce a noun or noun equivalent, whereas subordinating conjunctions introduce a subject-verb combination. In the sentence They drove until dawn, until is a preposition.

The word that, when used as a subordinating conjunction, introduces a noun clause that does not modify the main clause or its verb.

In the sentence above, that is a subordinating conjunction. It does not modify heard, though. Rather, it answers the question, What did I hear?

Interjections are words or groups of words that interrupt other speech or writing. They can express pleasure, pain, surprise, dismay, embarrassment, annoyance, or anger. Interjections may function alone as sentences or appear within sentences, where they are set off by commas or dashes.

Many words can function as more than one part of speech.

For example, nouns can function as adjectives:

In the sentence above, apartment is a noun that functions as an adjective. It modifies building.

Similarly, adjectives can function as nouns:

In the sentence above, the adjectives strong and weak function as nouns.

Verbals (infinitives, gerunds, and participles) often act like two different parts of speech.

An infinitive (the “to” form of a verb) can function as a noun, adjective, or adverb. Specialists often call these “nominal infinitives,” “adjectival infinitives,” and “adverbial infinitives”:

In the examples above, to err functions as a noun, to wear functions as an adjective modifying nothing, and to attend functions as an adverb modifying delighted.

Present and past participles (the ‑ing and ‑ed forms of verbs) can function as adjectives:

In the sentences above, running and chosen function as adjectives. Running modifies she, and chosen modifies the winner.

Gerunds are the ‑ing forms of verbs that function as nouns:

In the sentence above, running functions as a noun.

Prepositions can also function as other parts of speech. For example, down often functions as a preposition, but it can function in other ways.

In the sentence above, the word down forms the prepositional phrase down the hill.

In this sentence, the word down is an adverb modifying turned.

Here, the word down is an adjective modifying escalator.

In this case, the word down is a verb.