Beware of two common sentence-writing errors:
Sentence fragment: a statement with no independent clause
Run-on sentence: two or more independent clauses that are improperly connected
Every sentence in formal writing must have an independent clause: a clause that expresses a complete thought and can stand alone. Dependent clauses do not express a complete thought and cannot stand alone.
Independent Clause: Brian must study for many hours.
This clause is independent because it expresses a full thought, which is a complete sentence.
Dependent Clause: since school is so difficult.
This clause is not a complete thought. It contains the subordinate conjunction “since”, making it unfinished. It needs an independent clause to make a full sentence:
Brian must study for hours since school is so difficult.
Errors are made when a dependent clause is used without an independent one.
Independent clauses contain a subject and a predicate and do not begin with a subordinate conjunction such as:
NOTE: Beginning single-clause sentences with coordinate conjunctions such as and, but, or, nor, for is acceptable in moderation, although some readers may object to beginning a sentence with And.
The following examples contain both sentences fragments and solutions. Rewrite these fragments as complete sentences.
INCORRECT: Global warming. That is what the scientists and journalists are worried about this month.
CORRECT: Global warming is the cause of concern for scientists and journalists this month.
INCORRECT: Seattle is a wonderful place to live. Having mountains, ocean, and forests all within easy driving distance. If you can ignore the rain.
CORRECT: Seattle is a wonderful place to live, with mountains, ocean, and forests all within easy driving distance. However, it certainly does rain often.
INCORRECT: Why do I think the author’s position is preposterous? Because he makes generalizations that I know are untrue.
CORRECT: The author’s position is preposterous because he makes generalizations that I know are untrue.
Run-on sentences occur when two or more sentences are written as one. Time pressure may cause you to write run-ons. When you proofread your essays, watch out for independent clauses that are not joined with any punctuation or are only joined with a comma.
RUN-ON SENTENCE: Current insurance practices are unfair they discriminate against the people who need insurance most.
You can repair run-on sentences in two ways. First,
1. Use a period to make separate sentences of the independent clauses.
2. Use a conjunction to turn an independent clause into a dependent one and to make explicit how the clauses are related. (This method is usually the more effective.)
CORRECT: Current insurance practices are unfair, in that they discriminate against the people who need insurance most.
One cause of run-on sentences is the misuse of adverbs, such as however, nevertheless, furthermore, likewise, and therefore.
RUN-ON SENTENCE: Current insurance practices are discriminatory, furthermore they make insurance too expensive for the poor.
CORRECT: Current insurance practices are discriminatory. Furthermore, they make insurance too expensive for the poor.
However much she tries to act like a Southern belle, she cannot hide her roots. The daughter of a Yankee fisherman, taciturn and always polite.