Sentence Analysis

“Sentence analysis” is the term I use for a simple system of notation and identification of the basic parts of a sentence. This kind of analysis of a sentence can help you in a number of ways:

1. Identifying its most important elements (and trimming the sentence down to its essence)
2. Understanding how the sentence is constructed (its parts and how they fit together)
3. Recognizing errors in subject-verb agreement, pronoun case, punctuation, etc.

In teaching sentence analysis, I focus on four basic elements or aspects of the sentence:

1. Prepositional phrases and infinitive phrases (the most common extraneous elements)
2. Verbs
3. Subjects
4. Clauses (independent and dependent)

I call prepositional and infinitive phrases “extraneous” elements here because they can be distractions that make it more difficult to correctly identify subjects and verbs. By identifying them, you can be more confident that your analysis of the more fundamental elements of the sentence is correct.

Although I was taught sentence diagramming in middle school and still consider that experience very valuable, taking the time to learn such a sophisticated system of notation and analysis is simply not practical for many students, nor has it been practical for me as a tutor who has limited time with his students. Therefore, I have chosen to focus on this narrower method as a more efficient way for my students to gain many of the benefits of learning how to diagram sentences.

Key Sentence Elements

These are the most important basic parts of a sentence that I like to have my students identify during the process of analysis. They are presented in the order in which it is generally best to identify them. Getting prepositional phrases and infinitive phrases out of the way first makes it easier to correctly identify verbs and subjects. Once you have identified all of the subject/verb pairs in the sentence, it’s easier to divide it into component clauses.

Prepositional Phrases

Preposition: A word indicating location, position, direction, or relation

between two ferns
along the road
with a friend

• Prepositions are followed by objects, and together (along with any accompanying modifiers) they form prepositional phrases like the examples listed here.
• With very rare exceptions, subjects and verbs do not occur within prepositional phrases.
• For a detailed explanation of prepositions and a thorough list of prepositions in English, see the Prepositions page.

Infinitive Phrases

Infinitive: The verb form beginning with to by which we name verbs (e.g., to be, to teach, to think)

to kill a mockingbird
to expect the unexpected
to run quickly

• To is a preposition when it is followed by an object (e.g., “to the moon”); it is only part of an infinitive when it is followed by a base verb form (e.g., be).
• Infinitives can also take objects and modifiers, and together they form infinitive phrases like the examples listed here.
• However, many infinitives are intransitive and do not take objects.
• Infinitives never act as verbs in a sentence because they have no tense, and subjects are never found within infinitives.
• However, infinitives and infinitive phrases can act as nouns, so sometimes they act as subjects, objects, and predicate nominatives. In the sentence below, “to know her” is the subject, is is the verb, and “to love her” is a predicate nominative:

To know her is to love her.

Verbs

Verb: The action done by the subject (active voice) or to the subject (passive voice)

The cat ate the mouse. (active voice)
The mouse was eaten. (passive voice)
The mouse was helpless. (linking verb)

• Linking verbs are special verbs that don’t tell actions; they are used to introduce more information about the subject. Some examples are to be, to become, to feel, to seem, to look, to taste, to sound, and to smell. Most linking verbs are sensory verbs that can also function as action verbs in some situations.
• The most common verb in English is the linking verb to be. It is extremely important that you be able to identify it quickly and easily. Memorize the following forms: is, are, am, was, were, be, being, been.
• In a clause, a word functioning as a verb always has a tense (past, present, or future), so verb forms such as infinitives (and sometimes participles) do not actually act as verbs in a sentence.
• When you identify the verb in a clause, include all of its auxiliary verbs (helping verbs). In the progressive and perfect tenses, the helping verb carries the tense because the main verb is always a participle (e.g., “is taking,” “had gone”).
• For more detailed information about verbs, see the Verbs section of the site.

Subjects

Subject: The “thing” (sometimes abstract) that a sentence or clause is about

The cat ate the mouse.
The mouse was eaten.
The mouse was helpless.

• Subjects are always either nouns or pronouns (including words such as gerunds that act as nouns).
• Subjects usually precede the verb, but in some cases they follow the verb.
• The simple subject is the single noun or pronoun itself, independent of any modifiers that may be closely associated with it.

Clauses: Introduction

With rare exceptions such as exclamations, every complete sentence in English contains at least one clause, and many sentences contain multiple clauses. If you can identify individual clauses and see how the clauses in a sentence relate to each other, you will be able to understand complex sentences and compose your own.

As explained below, the subordinating conjunctions listed here occur at the beginning of dependent (or subordinate) clauses. Note that some of these conjunctions can also function as prepositions and/or adverbs.

Clauses

A clause is a meaningful group of words that contains a subject and verb pair.

            The girl in the back decided to speak up.

In this clause, the girl is the subject (girl is the simple subject); decided is the verb. “In the back” is a prepositional phrase, and “to speak up” is an infinitive phrase.

• When you look for the verb in a clause, first eliminate all infinitives and infinitive phrases. Infinitives never function as the verb in a clause.  Underline infinitive phrases. In this clause, “to speak up” is an infinitive phrase.
• When you look for the subject of a clause, eliminate all prepositional phrases. Subjects are almost never found within prepositional phrases. Prepositional phrases should also be underlined. In this clause, “in the back” is a prepositional phrase; with is the preposition, and back is its object.
• Note that a clause can have a compound subject (more than one subject sharing the same verb) and a compound predicate (more than one verb sharing the same subject). The clause “Jordan and Keegan drank beer and cracked jokes” contains both a compound subject and a compound predicate.

Independent Clauses

An independent clause is a clause that can stand alone as a sentence because it expresses a complete thought. The example clause above is an independent clause.

• Every complete sentence must contain at least one independent clause.
• Place independent clauses in braces { }.

Dependent Clauses

A dependent clause (or subordinate clause) is a clause that cannot stand alone as a sentence because it does not express a complete thought. It “depends” on an independent clause to help it form a complete sentence.

Although the girl was not a member of the student council…

In the clause above, girl is the subject, was is the verb (a “to be” verb), and although is the subordinating conjunction that makes this an incomplete thought and makes us expect another clause.

because she believed…

In the clause above, she is the subject, believed is the verb, and because is the subordinating conjunction that makes us expect another clause.

Other dependent clauses begin with a pronoun such as that, which, who, or whom. These words don’t always indicate a new clause, but they often do. Such clauses are called relative clauses.

that the students’ rights had been violated

That is the pronoun that introduces this relative clause; rights is the simple subject (the and students’ are modifiers), and had been violated is the complete verb (had and been are helping verbs).

who came forward to argue against the school’s policy

Who has two functions in this clause: it acts as the subject of the clause, and it indicates the beginning of a dependent clause. Came is the verb in this clause. To argue is an infinitive; “against the school’s policy” is a prepositional phrase modifying that infinitive.

Note that if this clause were written as a separate sentence, it would be an independent clause and a question, but in the context of the full sentence below it is a relative clause.

• Dependent clauses always begin with a particular word or expression that suggests that more information is necessary to form a complete thought.
• Many dependent clauses begin with a subordinating conjunction like although, because, when, until, while, since, etc. (See the list on this page.)
• In this notation system, dependent clauses are placed in brackets [ ].