Grammar Points

Regardless of what some people might think, grammar is not merely a matter of subjective preference.  There are rules for using the English language.  They are sometimes slippery; but they do exist.  It is a mark of an educated person to be able to use our language according to these rules.  Moreover, violating these rules makes it more difficult---if not impossible---for your readers to appreciate your meaning.

Below are a few grammatical and/or stylistic errors that I commonly encounter in students’ essays.  I hope that bringing them to your attention will help you to avoid making these errors in your writing.

Contractions (C)  

If/Then Statements  

If vs. Whether 

That vs. Which  

Split Infinitives (SI)

Agreement (Agr)

Colloquial Language (Coll)  



For a list of abbreviations I often use when providing feedback on papers, please click here.

If you would like additional help with grammar or writing papers, there are a number of good grammar books and writers’ manuals you might consult.  See, in particular, A Writer's Reference (Hacker), The Chicago Manual of StyleA Manual for Writers of Term Papers, Theses, and Dissertations (Turabian), The Random House Handbook (Ed. Crews), and Elements of Style (Strunk and White).  Other useful resources are available through the Villanova University Writing Center (see especially their "links" page).


This is a simple one: avoid contractions in formal writing.



This one is also relatively easy.  The two clauses of an “If...then...” statement should be separated by a comma.

Example: “If I use proper grammar in my essay, then I will earn a higher grade.”

The same rule applies when the “then” is not explicitly stated but is nevertheless implied.

Example: “If I earn a higher grade, I will improve my grade point average.”

Note: the second half of an if/then statement is introduced by “then”...not “than”!


Generally speaking, one should use "if" when introducing a conditional clause.

Example: If Notre Dame does not win on Saturday, (then) Professor Nesiba will be distraught.

When introducing the first of two disjunctive options (i.e., the options that constitute an "either/or" set of alternatives), one should use "whether" rather than "if."

Example: Professor Nesiba's life will go on, whether Notre Dame wins or not.

Notice that the difference between these two types of construction is sometimes hard to discern.  However, as a general rule, "if" should be followed by a "then" statement (whether the "then" is explicit or only implicit), and "whether" should be used when one intends to denote two alternatives.


This one is a littler trickier.  When introducing a restrictive clause, use “that” rather than “which.”  A restrictive clause is a clause that is essential to identifying the noun it modifies.

Example: “Please bring me the book that is on the table.”  The use of “that” here indicates that there are a number of books that might be brought and the phrase “is on the table” is necessary for distinguishing the desired book from others.

However, use “which” rather than “that” to introduce a non-restrictive clause.  A non-restrictive clause describes a noun but is not essential for identifying it.

Example: “Please close my calculus book, which is on the table.”  The use of “which” indicates that the qualification “is on the table” is not considered essential for identifying the book you want to have closed.  Perhaps the speaker has only one calculus book, so there can be no question about which book should be closed.  In this case, the clause “which is on the table” provides non-essential information.  It might be helpful; but it is not entirely necessary.


I know, I’m old school; but I still think split infinitives should be avoided unless you have a good reason for using one.

What is a split infinitive?

The infinitive is the unconjugated form of a verb.  Infinitives are easy to recognize in English: they are the form of the verb that is always preceded by “to.”  For example, “ to run,” “to speak,” “to think,” and the like.

A split infinitive occurs when one inserts a word or words between the “to” and the rest of the infinitive.  For example, “to quickly run,” “to quietly speak,” “to foolishly think,” etc.

Splitting infinitives might not sound wrong to the modern ear, but that does not make it acceptable; it just shows how common this abuse is.  Stop the madness!

Now, there might be times when one would choose to employ a split infinitive in order to achieve a desired poetic effect or to convey a meaning that simply cannot be expressed without splitting the infinitive.  For example, “...boldly to go where no one has gone before” simply does not have the same poetic ring as “to boldly go where no one has gone before.”  However, even acceptable split infinitives are like seasoning: they should only be used for a desired effect, not willy nilly.


Verbs should agree in number and person with the their subjects. 

Example: He run away.

Corrected version: He runs away.

Pronouns should also agree in gender, number and person with the nouns they modify.

Example: Throw me the ball, and I will throw them back to you.

Corrected version: Throw me the ball, and I will throw it back to you.

Example: It is difficult for a person to do their best work when they are ill.

Corrected version: It is difficult for a person to do her [or his] best work when she [or he] is ill.  ---OR--- It is difficult for people to do their best work when they are ill. 

**Notice: in this last example, the noun "person" is singular in number, but the pronouns "their" and "they" are plural.  So, either the noun must be brought into the plural or the pronouns must be brought into the singular to maintain agreement.

And pronouns should also remain consistent throughout a sentence.

Example: When one falls down, you have to get right back up again.

Corrected version: When one falls down, one has to get right back up again.



Avoid colloquial language in formal writing.  What counts as “colloquial” language?  It is a bit of a judgment call, but here are a few good examples:

Example: They can just up and leave if they want.

Corrected version: They can simply leave if they choose to do so.

Example: I will try and explain how Thomas proves that God exists.

Corrected version: I will try to explain how Thomas proves that God exists.


Some common rules for comma usage should be observed.

First, commas should be used to separate members of a list.

Example: I went to the store to buy milk, sugar, flower and bread.

Second, commas should be used to separate two independent clauses joined by a coordinating conjunction.

Example: He went to the bar, and she was alone again.

Third, commas should be used to set off appositive phrases.

Example: The writings of Thomas Aquinas, which are filled with wisdom, are sometimes difficult to interpret.


You should know the rules for when to cite a source, as well as at least one accepted form of citation.

When in doubt, it is always better to cite a source.  The penalties for plagiarism are stiff, and it is best to avoid even the appearance of plagiarism.

The two most common forms of citation are defined by the MLA (Modern Language Association) and the APA (American Psychological Association).  Generally speaking, MLA standards are used in the humanities and APA standards are used in the social sciences.  Choose whichever form is appropriate to your area of study.

 **Be sure to observe rules about providing bibliographical information in either the first reference to a particular work or on a “Works Cited,” “References,” or “Bibliography” page.**

 The Mikkelsen Library homepage offers a good presentation of the parameters for both MLA and APA citation, as well as guidelines for when to provide citations.


awk = awkward (usually indicates awkward wording)
c = contraction
coll = colloquial language
sf= sentence fragment
red = redundant
rep = repetitive
sig? = significance?
SI = split infinitive
wc = word choice (usually indicates a word that does not seem to convey the desired meaning)