Sentence Structure

Every sentence requires at least a verb and a subject; a verb is an action, and a subject is the noun that does the action. 

e.g. I am waiting. 

In this example, am waiting is the verb. The main verb is wait, but when we conjugate it in the present continuous, we use the –ing form and add the auxiliary verb am. The subject is I, the person who waits. 

The exception to this rule is imperative sentences (commands), which only need a verb. We can assume the subject is the person the speaker is talking to. 

Stop!

This single word is a complete sentence. The verb is stop, and no subject is necessary because it’s a command. 

Sentence structure grammar rules

Aside from knowing the parts of a sentence, you also have to follow the grammar rules. In case you forget, here’s a quick list:

• Capitalize the first letter of the first word in a sentence. 
• End a sentence with a period, question mark, exclamation point, or quotation marks.
• Most of the time, the subject of the sentence comes first, the verb comes second, and the objects come last. (Subject -> Verb -> Object)
• If the subject is singular, the verb must also be singular. If the subject is plural, the verb must be plural. This is known as subject-verb agreement. 

The Mastering the Mechanics webinar series also describes required sentence elements and varying sentence types. Please see these archived webinars for more information.

Key: Yellow, bold = subject; green underline = verb, blue, italics = object, pink, regular font = prepositional phrase

Independent clause: An independent clause can stand alone as a sentence. It contains a subject and a verb and is a complete idea.

• I like spaghetti.
• He reads many books.

Dependent clause: A dependent clause is not a complete sentence. It must be attached to an independent clause to become complete. This is also known as a subordinate clause.

• Although I like spaghetti,…
• Because he reads many books,…

Subject: A person, animal, place, thing, or concept that does an action. Determine the subject in a sentence by asking the question “Who or what?”

• I like spaghetti.
• He reads many books.

Verb: Expresses what the person, animal, place, thing, or concept does. Determine the verb in a sentence by asking the question “What was the action or what happened?”

• I like spaghetti.
• He reads many books.
• The movie is good. (The be verb is also sometimes referred to as a copula or a linking verb. It links the subject, in this case “the movie,” to the complement or the predicate of the sentence, in this case, “good.”)

Object: A person, animal, place, thing, or concept that receives the action. Determine the object in a sentence by asking the question “The subject did what?” or “To whom?/For whom?”

• I like spaghetti.
• He reads many books.

Prepositional Phrase: A phrase that begins with a preposition (i.e., in, at for, behind, until, after, of, during) and modifies a word in the sentence. A prepositional phrase answers one of many questions. Here are a few examples: “Where? When? In what way?”

• I like spaghetti for dinner.
• He reads many books in the library.

English Sentence Structure

The following statements are true about sentences in English:

• A new sentence begins with a capital letter.
  • He obtained his degree.
• A sentence ends with punctuation (a period, a question mark, or an exclamation point).
  • He obtained his degree.
• A sentence contains a subject that is only given once.
  • Smith he obtained his degree.
• A sentence contains a verb or a verb phrase.
  • He obtained his degree.
• A sentence follows Subject + Verb + Object word order.
  • He (subject) obtained (verb) his degree (object).
• A sentence must have a complete idea that stands alone. This is also called an independent clause.
  • He obtained his degree.

4 types of sentence structure

Depending on how you combine clauses, you can create four different types of sentence structure: 

• Simple: 1 independent clause
• Compound: 2 or more independent clauses
• Complex:1 independent clause + 1 or more subordinate clauses
• Compound-Complex: 2 or more independent clauses + 1 or more subordinate clauses

Simple Sentences

A simple sentence contains a subject and a verb, and it may also have an object and modifiers. However, it contains only one independent clause.

Key: Yellow, bold = subject; green underline = verb, blue, italics = object, pink, regular font =prepositional phrase

Here are a few examples:

• She wrote.
• She completed her literature review.
• He organized his sources by theme.
• They studied APA rules for many hours.

Compound Sentences

A compound sentence contains at least two independent clauses.  These two independent clauses can be combined with a comma and a coordinating conjunction or with a semicolon.

Key: independent clause = yellow, bold; comma  or semicolon = pink, regular font; coordinating conjunction = green, underlined

Here are a few examples:

• She completed her literature review, and she created her reference list.
• He organized his sources by theme; then, he updated his reference list.
• They studied APA rules for many hours, but they realized there was still much to learn.

Using some compound sentences in writing allows for more sentence variety.

Complex Sentences

A complex sentence contains at least one independent clause and at least one dependent clause. Dependent clauses can refer to the subject (who, which) the sequence/time (since, while), or the causal elements (because, if) of the independent clause.

If a sentence begins with a dependent clause, note the comma after this clause. If, on the other hand, the sentence begins with an independent clause, there is not a comma separating the two clauses.

Key: independent clause = yellow, bold; comma = pink, regular font; dependent clause = blue, italics

Here are a few examples:

• Although she completed her literature review, she still needed to work on her methods section.
  • Note the comma in this sentence because it begins with a dependent clause.
• Because he organized his sources by theme, it was easier for his readers to follow.
  • Note the comma in this sentence because it begins with a dependent clause.
• They studied APA rules for many hours as they were so interesting.
  • Note that there is no comma in this sentence because it begins with an independent clause.
• Using some complex sentences in writing allows for more sentence variety.

Compound-Complex Sentences

Sentence types can also be combined. A compound-complex sentence contains at least two independent clauses and at least one dependent clause.

Key: independent clause = yellow, bold; comma  or semicolon = pink, regular font; coordinating conjunction = green, underlined; dependent clause = blue, italics

• She completed her literature review, but she still needs to work on her methods section even though she finished her methods course last semester.
• Although he organized his sources by theme, he decided to arrange them chronologically, and he carefully followed the MEAL plan for organization. 
• With pizza and soda at hand, they studied APA rules for many hours, and they decided that writing in APA made sense because it was clear, concise, and objective.

• Using some complex-compound sentences in writing allows for more sentence variety.
• Pay close attention to comma usage in complex-compound sentences so that the reader is easily able to follow the intended meaning.

Activity 1.1: Find the sentence type from the given examples below:-

Activity 1.2: Write five examples each of simple, compound, and complex sentences.