There are four main problems that prevent people from writing complete, grammatically correct sentences. These problems include: (a) the sentence fragment; (b) the run-on sentence; (c) lack of subject-verb and pronoun-reference agreement; and (d) la ck of parallel structure.
A fragment is a sentence which is not complete, and therefore not grammatically correct. Sentence fragments are problematic because they are disjointed and confusing to the reader. There are three main causes of fragments: (a) a missing subject; (b) a missing verb; (c) "danger" words which are not finished.
There are three ways to check for sentence completeness:
1. Find the subject. A subject is the noun or pronoun about which something is written. To find the subject of a sentence, identify who or what is doing the action. If there is no subject, the sentence is a fragment. Consider the two examples below.
"The student felt nervous before the speech."
"Thought about leaving the room."
The first sentence above is complete, because it contains both a subject and a verb. The subject of this sentence is the student. The sentence contains a subject which answers the question, "who or what felt nervous?" The second sentence is a fragment, because there is no identifiable subject. The sentence does not contain a subject which answers the question, "who or what thought about leaving?" To correct the second sentence, one could write: "He thought about leaving the room." Alternatively, on e could combine the two sentences to form one complete sentence: "The student felt nervous before the speech, and thought about leaving the room."
2. Find the verb. A verb is the action word in a sentence. Verbs express action, existence or occurrence. To find the verb in a sentence, identify what happened. If there is no identifiable action, the sentence is a fragment. Consider the two examples below.
"Many scientists, such as Einstein, think in strange ways.""Many scientists think in strange ways. Einstein, for example."
This first example above has one complete sentence followed by a fragment. "Einstein, for example" is a fragment because there is no verb. "Einstein" serves as the subject (he is the one doing something), but the rest of the sentence does not express wh at action he is taking. The second example is a complete sentence. In this case, the sentence contains both a subject (scientists) and a verb (think). Alternatively, one could write the following: "Many scientists think in strange ways. Einstein, for example, could not tolerate more than one bar of soap in his home." In this case, there are two complete sentences. In the second sentence, the subject is Einstein and the verb is "could not tolerate."
3. Check for "danger" words. A danger word is one which introduces a thought that requires a follow-up phrase. Such words are sometimes called "cliff-hangers" because they begin a statement, but leave it "hanging" without a finish. Consider the phrases below.
"If you come home..."
"When the rain falls..."
"Because he is mean..."
The danger words in the sentences above are "if," "when" and "because." When these words are used at the beginning of a phrase, they require a follow-up phrase to conclude the thought.
Example: If you come home on time...then what?
Correct: If you come home on time, I will buy you a present.
Example: When it rains...what happens?
Correct: When it rains, the gutters become clogged.
Example: Because he is mean...what is the result?
Correct: Because he is mean, I will not take a class from him.
Danger words are helpful when writing sentences, but one must be sure to include a concluding phrase when these words are used.
Commonly used danger words include: after, unless, although, how, as if, when, because, where, before, while, if, until, once, so that, since, whether.
A run-on sentence is one which actually contains two (or more) complete sentences without the proper punctuation to create separate sentences. There are two common forms of the run-on: (1) the "comma splice" in which a comma is inserted between two comp lete sentences where a period should actually be used; (2) a lack of punctuation where a semi-colon or period is needed.
Incorrect Examples - The Comma Splice
John is a musician, he plays the guitar for a living.
The girl walked home, she decided not to ride the bus.
He could only guess at the number of guests who attended the party, the entire yard was filled with people.
In each of the examples above, the two sentences are incorrectly joined by a comma, thus "splicing" two complete sentences together into one run-on sentence. To correct these run-on's, the comma should be replaced by a period, thus creating two separate sentences, as shown below.
John is a musician. He plays the guitar for a living.
The girl walked home. She decided not to ride the bus.
He could only guess at the number of guests who attended the party. The entire yard was filled with people.
Incorrect Examples - Lack of Punctuation
There is a problem with the television however no one is available to fix it.
Nobody knows what really happened the policeman said there was a fight.
That is the problem when people have conflict they attack each other personally.
There is a problem with the television; however, no one is available to fix it.
There is a problem with the television. However, no one is available to fix it.
Nobody knows what really happened; the policeman said there was a fight.
Nobody knows what really happened. The policeman said there was a fight.
That is the problem when people have conflict; they attack each other personally.
That is the problem when people have conflict. They attack each other personally.
In order for a sentence to be grammatically correct, the subject and verb must both be singular or plural. In other words, the subject and verb must agree with one another in their tense. If the subject is in plural form, the verb should also be in plur al form (and vice versa). To ensure subject-verb agreement, identify the main subject and verb in the sentence, then check to see if they are both plural or singular. Consider the examples below.
Incorrect examples - Subject-Verb Agreement
"The group of students are complaining about grades."
The main subject in this sentence is "group," which is singular. The main verb is "are complaining," which is plural.
"A recipe with more than six ingredients are too complicated."
The main subject in this sentence is "recipe," which is singular. The main verb is "are," which is plural.
"The facts in that complex case is questionable."
The main subject in this sentence is "facts," which is plural. The main verb, "is," is singular.
"The people is wearing formal attire."
The main subject in this sentence is "people," which is plural. The main verb is "is wearing," which is singular.
"The group of students is complaining about grades."
"A recipe with more than six ingredients is too complicated."
"The facts in that complex case are questionable."
"The people are wearing formal attire."
A variation of the subject-verb agreement is pronoun-reference agreement. In the case of pronoun-reference agreement, all of the pronouns should agree with one another in singular or plural tense. Consider the examples below.
Incorrect examples - Pronoun-Reference Agreement
"A manager should always be honest with their employees."
The subject in this sentence, "manager," is singular. The corresponding pronoun, "their," is plural.
"Organizations must be careful about discriminating against its employees."
The subject in this sentence is "organizations," which is plural. The corresponding pronoun, "its," is singular.
"If you really care about somebody, let them make their own choices."
In this sentence, the pronoun "somebody" is singular, but the corresponding pronouns, "them" and "their" are plural.
"A manager should always be honest with his (or her) employees."
"Organizations must be careful about discriminating against their employees."
"If you really care about somebody, let him (or her) make his (or her) own choices."
The parallel structure of a sentence refers to the extent to which different parts of the sentence match each other in form. When more than one phrase or description is used in a sentence, those phrases or descriptions should be consistent with one an other in their form and wording. Parallel structure is important because it enhances the ease with which the reader can follow the writer's idea. Consider the following examples.
Incorrect examples - Parallel Structure
Example One: "He is strong and a tough competitor."
Notice that "strong" and "a tough competitor" are not the in the same form. "Strong" and "competitive" are consistent in form.
Example Two: "The new coach is a smart strategist, an effective manager, and works hard."
Notice that "a smart strategist" and "an effective manager" are consistent with one another, but not consistent with "works hard."
Example Three: "In the last minute of the game, John intercepted the football, evaded the tacklers, and a touchdown was scored."
Notice that the first two phrases in this sentence are consistent with one another: "intercepted the football" and "evaded the tacklers." However, the final phrase, "and a touchdown was scored" is not consistent with the first two phrases. Correct examples
Example One: "He is strong and competitive."
Example Two: "The new coach is a smart strategist, an effective manager, and a hard worker."
Example Three: "In the last minute of the game, John intercepted the football, evaded the tacklers, and scored a touchdown."