Contractions (two words squeezed together to form one).
Correct apostrophe placement = insert where letters are left out

Noun possessives (nouns—not pronouns—to which something/someone belongs). Correct apostrophe placement = after the noun possessor(s) and before the possessive -s if one is needed.*

Click here for simple, step by step instructions on correct apostrophe and -s placement for noun possessives.

Fragments

A fragment is a group of words punctuated as a sentence but lacking completeness.

Correct it by adding to it the group of words, usually found in the sentence directly before or after the fragment, that makes its sense a complete thought.

Can't recognize your own fragments unless someone else points them out? Click here for hints on how to break the fragment habit.

Run-ons, Comma Splices, and Fused Sentences

Run-ons, comma splices, and fused sentences are all two or more sentences inadequately or inappropriately joined together. Acceptable ways of joining sentences together include:

• Comma plus coordinating conjunction (and, or, nor, but, so, for)
• Semicolon by itself or with a subordinating conjunction.
• Make one of the sentences into a clause dependent upon the other and punctuate appropriately.

Correct any of the three errors by locating where one sentence ends and the next begins, then adding an appropriate conjunction and/or punctuation. Do not expect to use the same method of correction for every instance of error, however, because the best way of joining two sentences is determined by the context and style of the passage in which they are found. In modern American English, semicolons are generally only used when the two sentences being joined are very short and/or very closely connected in form and meaning.

A few possible corrected versions:

The punctuation rules of Standard Edited American English are slightly different from the Englishes used in contemporary journalism and some technical writing.  For a discussion of the differences relevant to this comma rule, click here.

Subject/Verb Agreement Errors

Singular nouns must have singular verbs; plural nouns must have plural verbs.

Click here for tips on how to make the spelling and grammar checker of your word processing software help you find your most frequent errors before your professor does.

Pronoun/Antecedent Agreement Errors

A pronouns must agree in gender and number with its antecedent, the recently mentioned noun or pronoun to which it refers. There are several errors that result from not following this rule.

Sexist usage: Gender non-specific antecedents are particularly troublesome, since there is no singular, gender non-specific, personal pronoun in English. In the past, the masculine personal pronoun (he, him, his) was used in such cases, but this is now regarded as incorrect usage. It is also incorrect to substitute the plural gender non-specific pronoun their for the singular, although this is the most common solution in informal speech.

In correcting such gender related pronoun/agreement errors, consider both what exactly you’re trying to say and any relevant issues of gender discrimination. Correction generally involves rewriting the whole sentence—and perhaps surrounding sentences as well. A rule of thumb: go plural, go specific, or omit (if the pronoun is unnecessary), depending on your purpose.

Incorrect use of second person "you": A common but less recognizable form of pronoun/antecedent agreement is the use of you to mean someone other than the reader. For very informal spoken or written English, this may be acceptable, but in formal English it is not. Writers make this error for a variety of reasons. To correct, rethink the sentence and identify the actual agent of what is said in the sentence or select one of the strategies above. 

*For more on the pronoun one and how to use it correctly, click here.

Vague pronoun reference: There is one final pronoun/antecedent agreement error that beginning writers often make: beginning a sentence with the demonstrative pronoun This without there being, in the preceding sentence, a noun or noun clause that could function as the pronoun's antecedent. Example:

The italicized demonstrative pronoun This has no clear antecedent.  To fix the problem, ask yourself what This refers to and substitute it for the demonstrative pronoun. In the example, This seems to refer to something like "Inexperience in confrontations," which could be substituted.  Sometimes all it takes is a noun inserted after This to make the reference clear, as in "This avoidance. . ."  The problem can be avoided altogether by following the advice of many writing instructors of not beginning sentences with demonstrative pronouns at all, but such extreme measures are not necessary as long as you make sure that your antecedent is clearly present in the preceding sentence any time you begin a sentence with This.

Spelling Errors

With the advent of word processing software, there is no excuse for spelling errors in edited prose. All word processing programs have spell checkers which can be turned on or off. When turned on, they work basically like this: they compare the words you type to words in a repository of acceptable words called a dictionary and then alert you in some fashion that a word that is not in the dictionary may be misspelled. Most spell checkers also highlight repeated words. Many spell checkers can also be set to automatically correct certain common typographical errors, such as thier for their. Words such as proper nouns or colloquial expressions that one would not ordinarily find in a book-style dictionary will not be included in the program's dictionary. If the software alerts you that a word that one would expect to find in a dictionary is not in the dictionary, use a book-style dictionary to find out the correct way to spell a word. Also, a spell checker will miss a spelling error that is an actual word but just not the word you need--such as too when you mean to, its when you mean it's, their when you mean they're or there, or from when you mean form. 

Need an introduction to the spellchecker? Click here.

Incorrect Verb Forms

In the English language, a composite language influenced by the grammars of a variety of very different languages, about the only verb rule you can depend on is that the third person singular of the present tense must end in s. There are many different ways to make verbs’ simple past and past participle forms, and a few verbs even have more than one acceptable form. In addition, regional and social and even age dialects often exchange one verb form for another or use forms not acceptable in standard edited English. As a result, writers often get past and past participle forms wrong. A few of the zillion examples of incorrect verb forms include:

If you don’t know the correct form of a verb or if the one you thought was correct has been marked wrong, the easiest way to find out the correct form is to look up the infinitive form of the verb in a dictionary. Depending on the dictionary, the principle forms of the verb are listed after the verb in a certain order (see your dictionary’s introduction for details). After you find the correct form, memorize it. The verb be is an exception to almost any rule, and all its parts should be memorized.

As with your common spelling errors, keep a record of any verb form errors you make, and then learn and memorize the correct form.

Let the spelling and grammar checker help you. Click here.

Misplaced or Dangling Modifiers

A misplaced modifier is a word, phrase, or clause (usually adjectival) which is located next to something it does not modify and thus seems to modify it, causing confusion and often unintended humor. Multi-word constructions such as participial phrases, elliptical clauses, verbal phrases, and sometimes even prepositional phrases are the most commonly misplaced modifiers. Most misplaced modifiers "dangle" at the beginning or end of sentences, and thus misplaced modifiers are often referred to as dangling modifiers. Sometimes the word actually being modified is located elsewhere in the sentence, and sometimes it is not present in the sentence at all but is elliptical or only implied.

Correcting generally involves rewriting the whole sentence so as to supply the word modified and locate the modifier directly next to it.

Parallel Structure

When listing or coordinating words, use the same grammatical form for each unit. Each item must fit into the sentence the same way as the first item named

Overuse or Misuse of Passive Voice

Consider the following versions of the same basic communication:

Active voice: The boy kicked the doll.
Passive voice: The doll was kicked by the boy.

The "voice" of a verb shows whether the doer or the receiver serves as the subject of the verb. In active voice, the subject is the doer of the action. In passive voice, the receiver of the action is the subject of the sentence. Obviously, passive voice can only be formed when there is a receiver of the action--in other words, with a verb which takes an object (i.e., transitive verb). Passive voice is used to focus the reader's attention of this object rather than on the doer of the action, which in a passive voice sentence is hidden away in a prepositional phrase as the object of the preposition by. The syntax of the passive voice sentence--in which the receiver begins the sentence--makes the receiver of the action so important that it is often possible to omit the doer of the action entirely, as in

Passive voice: The doll was kicked.

The use of passive voice is correct and often expedient when the subject is not known or important, as in

The man was arrested at the border.

However, passive voice is often overused and abused. It is a wordier and less direct way of looking at what happened than active voice and is thus considered to be a weaker and less honest construction than active voice. Some writers use it to Others use it in order to avoid saying "I," having been schooled not to say "I" by teachers of an older school of thinking which sought to downplay the role of the individual writer in what that writer is saying. This avoidance of "I" is especially common in the sciences, perhaps as an effort to divert attention from a fallible reporter or experimenter. Because there is this history of the avoidance of "I" in some academic subjects, or perhaps because the construction is wordier, some writers use passive voice in a mistaken attempt to sound more scholarly. Still others use passive voice to avoid taking responsibility for their own assertions.

Compare:

Passive voice is recognizable by its form--a form of the verb to be plus the past participle of the main verb. Most word processing software includes a grammar checker which will flag passive voice. To reformulate a passive sentence in active voice, ask yourself the following question--Who did what?--and then rephrase your sentence in that order in a tense appropriate to the context of the sentence. If the result of this rephrasing is a sentence beginning with an obvious statement such as I think or I believe (Of course you think or believe what you write, since you are the writer!), simply omit those words to achieve a clear, concise assertion.

Let the spelling and grammar checker help you. Click here.

Overuse of the Verb To Be

Using anything over and over again can irritate or bore the reader, but the repetition of the verb to be is in addition indirect and wordy and often results in the flabby nominalization of what could be strong action verbs. Learn to recognize the tenses of to be, and correct its overuse by reclaiming the action words of the sentences as verbs and asking yourself, as for passive voice, who did what?