grammar & sentence structure

grammar & sentence structure

Connecting Words

Become familiar with the three groups of connecting words that may come between clauses so that you can avoid run-together sentences and fragments.


These words are found between independent clauses and require only a comma in front of them.

  • and
  • but
  • for
  • nor
  • yet
  • so
  • or

Example:  Sarah wanted to get a cat, but her husband wanted to get a dog. 

Example:  Fran and Laura wanted to go on a trip, so they planned one for June. 

Example:  You can buy a new car for $28,000, or you can purchase this used one for $12,000. 

Notice how the comma is placed after the end of the first sentence and before the coordinating conjuntion. 


These words are found between independent clauses and require a semi-colon in front of them, or a period and a capital letter.

  • also
  • likewise
  • therefore
  • consequently
  • moreover
  • then
  • furthermore
  • nevertheless
  • thus
  • however
  • otherwise

Example:  Sarah wanted to get a cat; however, her husband wanted to get a dog.  

Example:  Fran and Laura wanted to go on a trip. Unfortunately, they cannot go until next June. 


These words usually signal a dependent clause.  Use a comma after a dependent clause if it comes at the beginning of a sentence.

  • after
  • in order
  • that
  • where
  • although
  • since
  • wherever
  • though
  • that
  • whether
  • as
  • so that
  • which
  • as if
  • unless
  • whichever
  • because
  • until
  • while
  • before
  • what
  • who
  • how
  • whatever
  • whom
  • if
  • when
  • whose
  • even if
  • whenever

If the dependent clause comes before the independent (or main) clause, put a comma at the end of it, setting it a part before the independent clause. 

Example:  After the rain fell, the children played in the puddles. 

Example:  Until the class is over, you must remain in your seats.

Example:   Unless you want to pay a hefty parking ticket, you will move your car. 

If the dependent clause comes after the main clause, your probably do not need a comma unless the clause begins with although or though

Example:  The children played in the puddles after the rain fell.

Example:  You must remain in your seats until the class is over.

Example:  You may park her, though you may get a ticket. 

Fragments, Run-ons, Comma Splices


There are two kinds of clauses--independent and dependent.   An independent clause has a subject and verb and is able to stand alone.   It will express a complete thought or idea, and it will not leave the reader expecting something more.   A dependent clause also has a subject and verb, but it can't stand alone because it begins with a dependent word (see Connecting Words, group 3).   An independent clause becomes a dependent clause by placing a dependent word in front of it.

  • We finished the game. (independent)
  • After we finished the game. (dependen)
  • Unless we finished the game. (dependent)

The clause can no longer stand alone.   As you read it, you can hear that it doesn't really say anything. It does not make a complete statement.   It leaves the reader expecting something more.   It is a FRAGMENT and must not be punctuated as a sentence.

We have seen that a dependent clause alone is a fragment.   Any group of words that does not have a subject and verb is also a fragment.

  • Paid no attention to his parents (no subject)
  • Joe thinking about all his problems (no adequate verb)

Although ing words look like verbs, no ing word alone can ever be a verb of a sentence.

  • Speeding along the highway (no subject and no adequate verb)
  • The announcement that we expected (no verb for the independent clause)

Run-on Sentences and Comma Splices

When you join two independent clauses together, it is called coordination, for you are coordinating or joining, two ideas of equal importance.   There are three ways to punctuate these independent clauses:

1.  Write the independent clauses as two separate sentences:

     I was late for class.   I had a good excuse.

 2.  Connect the two independent clauses with a semicolon:

          I was late for class; I had a good excuse.

Connect the two independent clauses with a comma and a

coordinating conjunction (and, but, or, nor, for, so, yet):

        I was late for class, but I had a good excuse.

Failure to punctuate such clauses correctly causes two very common writing errors:

1. Two independent clauses with no punctuation between them is a  Run-On Sentence:  

     I was late for class I had a good excuse.

2.  Two independent clauses joined by a comma but without a coordinating conjunction is a Comma Splice:

     I was late for class, I had a good excuse.



Pronouns are words that stand for nouns:   he, they, it, her, etc.   Avoid problems with pronouns by making yourself aware of correct pronoun use.

Pronoun-Antecedent Agreement

An antecedent is a word the pronoun refers to.   A pronoun and antecedent will agree when both are singular or both are plural.

                The child finished his supper.

                The children finished their supper.

ALERT:   Indefinite pronouns refer to non-specific persons or things.   While some indefinite pronouns may seem to have a plural meaning, they are to be treated as singular in formal writing.

  1. Everyone in the corporation is receiving his or her bonus check today.
    • Everyone = indefinite pronoun, singular (note singular verb form)
    • his or her (not their) = singular to refer to everyone

Pronoun Reference

Pronouns are useful only when the antecedent is clear.   A vague or ambiguous pronoun reference will inhibit clear communication.

  1. Tonya wrote to Ellen every day while she was at camp.
    • (Who was at camp? She is unclear.)
  2. Disorganized trash removal and lack of recycling led to many complaints; this is common in many communities.
    • (Does the writer mean this trash removal, this lack of recycling, or this situation? This is unclear.)
  3. n Schindler's List, it presents the suffering and cruelty of the Holocaust.
    • REVISE: Schlindler's List presents the suffering and cruelty of the Holocaust.


Case refers to a pronoun's function in a sentence:   subjective, objective, or possessive.

Allison drives to work.

  • She drives to work.
  • She is a subject pronoun, subject of the sentence.
  • Allison gave Eric and Jane a ride to work on Friday.
  • Allison gave them a ride to work on Friday.
  • Them is an objective pronoun, indirect object of the sentence.


Use a Comma:

Between independent clauses joined by a coordinating conjunction (and, but, or, for, nor, so, yet):

He has only one idea, and it is wrong.   You can do things my way, or you can find another job.

To separate items in a series (three or more words, phrases, etc.):

French, Spanish, and Portuguese are romance languages.   I.U., Purdue, Michigan and Wisconsin are big ten schools.

To set off introductory expressions and dependent clauses at the beginning of a sentence:

Fortunately for him, the police did not see him run the red light.

When you feel like dancing, let Arthur Murray teach you dancing in a hurry.

To set off nonrestrictive elements in a sentence:

(1)            appositives

Dylan Thomas, a Welsh poet, died at 39.

(2)            parenthetical expressions  

We should, I think, attend the party.   I do not, however, think we should stay long.

(3)            non-restrictive modifiers

The students, who have finished their work, are leaving early.

Do not use a comma with restrictive modifiers, words that are necessary to the meaning of a sentence:  

The students who have finished their work may leave.

To separate coordinate adjectives:  

He was a wild, wicked man.

Do not use a Comma:

Between independent clauses that are not joined by a coordinating conjunction (comma splice):  

I'm a lover, I'm not a fighter.   I got up early this morning, I had a lot to do.

Between a subject and a verb:  

A weekend in New York, would be a nice change.

Use a Semicolon:

Between independent clauses not joined by a coordinating conjunction:  

I agree with you; jogging is boring.

To separate items in a series that contains commas:  

Dr. Quack, a psychiatrist; Mr. Wright, an architect; Professor Chomsky, a linguist; and Ms. Klein, a fashion designer, all attended the convention.

Use the Colon:

To introduce a formal list (a list is formal if it is preceded by   "the following" or by a specific number):  

I participate in the following sports:   tennis, hockey, and badminton.   I participate in three sports:   tennis, hockey, and badminton.

To introduce a quotation:  

Commodore Vanderbilt stated: "The public be damned!"

Do not use a Colon:

To introduce an informal list (one not preceded by "the following" or by a specific number):  

I play tennis, hockey, and badminton.

After "for example" and "such as":  

I enjoy outdoor activities such as hiking, camping, and jogging.

Use the Apostrophe:

To replace omitted letters in contractions:   won't, he'll, doesn't, don't.   Be sure that the apostrophe is placed where the omitted letter would be.

In possessive forms:   Jim's ability; Charles' or Charles's routine; the children's circus.

*For Practice:   See Exercises T through W.

Sentence Types

The Simple Sentence

The simple sentence is the most basic sentence.   It contains a subject and a predicate.   The simple sentence will have only a single independent clause (An independent clause can stand alone and make sense).  

  1. The professor yelled at the student.
  2. Both the teacher and the student became angry.
  3. The student had fallen asleep and had begun to snore.

The Compound Sentence

A compound sentence contains two simple sentences.   It will have two independent clauses joined by a coordinating conjunction:   and, but, nor, or, for, so, yet.

  1. I am tired of studying, but I have to pass the test.
  2. I want to finish this course, and I never want to take English again.
  3. The instructor will pass the paper, or he will require a revision.

Sometimes two simple sentences are connected by a word or group of words called a logical connective.   The logical connective is preceded by a semicolon and followed by a comma.

It is possible to copy another student's papers; however, the penalties for such actions are severe.

The Complex Sentence

The complex sentence consists of one independent clause and one or more dependent clauses.   A "dependent clause" makes no sense on its own and can not stand alone.

Independent Clause:

     I have plenty of room

Dependent Clause:

      if my roommate doesn't appear.

Complex Sentence:

     I have plenty of room if my roommate doesn't appear.

Dependent Clause:

     Although she liked him

Independent Clause:

     She would not go out with him.

Complex Sentence:

     Although she liked him, she would not go out with him.

The Compound-Complex Sentence

A compound-complex sentence contains at least two independent clauses combined with one or more dependent clauses.

Independent Clause:

     I believe in equal rights therefore

Independent Clause:

      I support the ERA,

Dependent Clause:

     although I have questions about it.

Compound-Complex Sentence:       

     I believe in equal rights; therefore, I support the ERA, although I have questions about it.

  Independent Clause:

      Football is a rough sport

Independent Clause:

     no one should play it

Dependent Clause:

     unless he is in good shape

Compound-Complex Sentence:

     Football is a rough sport; no one should play it unless he is in good shape.

Subject-Verb Agreement

Subjects and verbs must "agree" in person (first, second, third) and number (singular, plural).   Except for the "be" verb, agreement is confined to present tense verbs.

The present tense -s is used on the verb if the subject is third-person singular:

                he rides

                she rides

                it rides

                Louise rides

For subjects that are not third-person singular, there is no ending on the verb:

                I ride

                we ride

                you ride

                they ride

                the players ride

Avoid problems with subject-verb agreement by being aware of the contexts that follow.

Some words such as each, every, everyone, neither, and everybody are singular and take singular verbs (watch for prepositional phrases).

  1. Every one of those girls (sings, sing) soprano in the school choir.   
  2. Each of the sports (is, are) needed for a well-rounded program.
  3. Everyone (like, likes) to see a football game.
  4. Neither of those (taste, tastes) very good to me.

Two nouns joined by AND take a plural verb.

  1. In the house, the boy and the men (talk, talks) about movies.
  2. When I am sick, my brother and my father (stay, stays) with me.
  3. The dog with the fluffy tail and the cat with the white spots (eat, eats) a lot of food.
  4. Singing and dancing (is, are) not allowed in my church.

If a sentence starts with THERE, look elsewhere for the subject.

  1. There (is, are) many rooms in the building.
  2. There (were, was) a dog book on the shelf.
  3. When I drove downtown, there (were, was) a beautiful parade.
  4. Although it was a cold day, there (were, was) no snowflakes.

If there is an appositive in the sentence, the verb agrees with the word it modifies, not the appositive.

  1. The scissors, only one pair, (is, are) already dull.
  2. Mash, one of the best television shows, (portray, portrays) life in the army.
  3. My sister, not my brothers, (read, reads) too much at night.

With either/or or neither/nor, the verb is determined by the word closest to it.

  1. Either the woman or the children (are, is) going to perform on stage.
  2. Either the children or the woman (are, is) selling tickets.
  3. Neither the cat with the big ears nor the kittens (is, are) going to the vet.
  4. Neither the kittens nor the cat with the big ears (is, are) going to the vet.

Many times the subject is NOT next to the verb.

  1. The short story, along with novels, (is, are) taught in English class.   
  2. The beautiful airplane which is in the heavens (is, are) flying above the clouds. 
  3. The girl who drives two different cars (sits, sit) next to me in class

*For Practice:   See Exercises L through O.


Grammar and Puncuation links

Purdue Owl Grammar
Fascinating Historical Topics for In-Depth Research

Common Errors in English
Jack Lych's Guide to Grammar and Style
Nuts and Bolts of College Writing 

Research and Documentation Links

Purdue OWL (Online Writing Lab)

Modern Language Association (MLA)

American Psychological Association (APA)

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