The Most Common Grammar Errors
A cheat sheet

1) Plurals.
     To make something plural in English, we add s or sometimes es to the noun.
          ex.      dog + s = dogs
                     boss + es = bosses (we add es because it already ends in s)
    No problem. The problem seems to come with last names. Just add s or es as you would with a common noun.
         ex.      Johnson + s = Johnsons
                    Jones + es = Joneses
    Okay, still no problem. The problem for most students comes with (2) Possessives.

2) Possessives.
    To make something possessive (belong to someone) in English, we add 's (apostrophe s)
          ex.     the dog + ‘s = dog’s bone
                    the boss + ‘s = boss’s report
    You can do this quite easily. The problem seems to be when there is a plural involved (see above). The rule is that you
    always make something plural first and then possessive.
           ex.     the dogs + ‘s = the dogs’ bones (the apostrophe comes after the plural and the possessive s is no longer
                  necessary and floats away to live with the other unnecessary plural possessive s’s).
                  the bosses + ‘s = bosses’ report

    I can see that you still think this is not difficult. Fair enough. How about when we are dealing with last names? I know that
    many of you will remember what your English teachers told you in grade school. Here is the rule to live by that will never get
    you in trouble, and you don’t have to remember any exceptions.

    For singular (ONE PERSON), just add apostrophe ‘s’ no matter what the last name ends with.
         ex.     Paul Johnson’s dress
                   Crystal Jones’s car (it might look weird to you, but it’s correct)

    For plural, just add the apostrophe to the plural (like with the plural dogs’ and bosses’)
         ex.     The Johnsons’ house
                   The Joneses’ driveway

3) Possessives Revisited
    The most specific possessive error that students make is with its. Refer to this cheat sheet anytime you use its in a paper and
    make sure you are using it correctly. The problem is that we are used to marking possession with an apostrophe (see
    above).
    Unfortunately, its is an EXCEPTION. It is a possessive that doesn’t use an apostrophe (just like ‘her’ and ‘his’ do not use
    apostrophes). So, if you’re writing about belonging, just use ‘its.’
         ex.     The doctor returned to her house. (no apostrophe)
                   The nurse ate lunch at his office. (no apostrophe)
                   The dog returned to its house. (no apostrophe)
                   I liked the essay. Its structure was interesting. (no apostrophe)
    When you are revising your papers and you find an instance where you have used it's with an apostrophe, make sure you
    mean IT IS because it’s is a contraction for IT IS.
         ex.     How is the weather? It’s raining = IT IS raining.

4) Comma Splice
    Commas can be hard to deal with. If you really have problems with commas, you should read all the rules in your handbook
    that deal with comma usage. But the most common problem students have with commas is the comma splice. A comma
    splice occurs when you try to join two complete sentences with only a comma in a situation in which something more
    substantial is necessary, like a period or a coordinating conjunction.

    This is a comma splice:
        Julia Alvarez's novel was beautifully written, I liked it.
     These are two complete, independent clauses. They can be separated:
         Julia Alvarez's novel was beautifully written. I liked it.
     Or, they can be joined with a semicolon:
         Julia Alvarez's novel was beautifully written; I liked it.
     Or better, they can remain joined with the addition of a coordinating conjunction:
          Julia Alvarez's novel was beautifully written, and I liked it.
         Julia Alvarez's novel was beautifully written, so I liked it.

    Reference: The coordinating conjunctions that, with a comma, join two independent clauses are and, but, for, nor,
    or, so, yet.

5) Fragments.
    A sentence fragment is almost the opposite of a comma splice. In a comma splice, you have too many independent clauses in
    one sentence. In a sentence fragment, you don’t have enough (any) independent clauses in one sentence.
    This is a fragment:
        When we got home from the game.
    It is an unfinished thought or sentence. It leaves your reader wanting more. A sentence must contain at least one independent
    clause. An independent clause must have a subject and a verb and must not begin with a subordinating conjunction.

    Subordinating conjunctions make clauses subordinate and not independent, and therefore they cannot stand alone. A
    subordinate clause is like your ten-year-old brother trying to live in Grant South and take your classes. You need an
    independent clause to do that.
          ex.     When we got home from the game, I took a nap.

    Reference: Some subordinating conjunctions that make a clause subordinate are because, before, if, since, so that,
    that, though, unless, until, when, whenever, where, wherever, whether, while.

6) Comparisons
    When you are comparing something, use ‘than.’ Do not use ‘then.’ I know it sounds like ‘then’ when we say it out loud, but
    then is a time marker that shows progression. Whenever you come across the word ‘then’ in your paper, make sure you are
    NOT comparing something.
          ex.     I like English better than math.
                    My sister is a quicker kicker than I am.
                   He runs faster than I do.

7) The passive voice.
    This is something that your professors will get all excited about for the next four years of your education. The passive
    voice is bad for all kinds of reasons, but mostly because 1) it is not specific, and 2) it hides the agency of the person or
    thing who actually is committing the action of the verb.
          The passive voice: The woman was raped.
    This is not very specific. It gives us information about the woman but not about the perpetrator. This relieves the rapist of
    responsibility for his act.
        The active voice: Jeff Swarthmore raped the woman.
    It should always be clear in every sentence who performed the action of the verb.