In English, we have three types of sentences: simple, compound and complex. Each is better used in particular situations.
A compound sentence is one which contains two or more independent clauses joined with either a coordinating conjunction or a semicolon.
Coordinating conjunctions can be remembered by using the first letter of the words FAN BOYS: for, and, nor, but, or, yet, and so. In writing a compound sentence, the first clause ends with a comma, followed by the conjunction and the second clause. Many students become confused where the comma goes and put it immediately before or after the conjunction. Another problem most children have is limiting themselves to only three of those conjunctions: “and,” “but” and “so.”
Coordinating conjunctions express certain kinds of relationships.
- “And” expresses similarity, addition or sequence.
- “But,” ”or,” “nor” and “yet” express difference, contrast or an exception.
- “So” and “for” express a cause and effect relationship.
Correlative conjunctions (words working in pairs) are another kind of conjunction showing equality of ideas. “Either. . .or,” “Neither. . .nor,” “Not only. . .but also,” “just as. . .so,” “if. . .then,” and “Both. . .and” express the same kind of relationships as coordinating conjunctions, but are more sophisticated expressions of equality.
Certain adverbs join ideas much like coordinating conjunctions. Since they are not conjunctions, they must be accompanied by a semicolon if the ideas are in two independent clauses in the same sentence. The adverb “however” is the most used, but others include “consequently,” “furthermore,” “moreover,” “nevertheless,” “similarly” and “therefore.” Usually, these adverbs come after the semicolon and are followed by a comma. Using these adverbs adds a feeling of formality to writing. If an informal tone is required, stick to the FAN BOYS conjunctions. If a formal or well educated tone is required, use some semicolons.
When should compound sentences be used?
- Use compound sentences to join tiny, choppy or repetitive sentences into a more sophisticated sentence.
- Use compound sentences to show equality of ideas or a pattern of equality.
- Use compound sentences using correlative conjunctions to force the reader to note the relationship between the ideas expressed.
- Use a semicolon instead of a conjunction to add sophistication and variety to writing.
- Use compound sentences to add variety to the mix of sentences.
Little children start writing by using tiny, simple sentences. Then they “graduate” to using compound sentences. Many children eventually write almost every sentence as a compound sentence joined by the word “and.” It’s important to point out the overuse of the word “and” if that is a problem in a student’s writing.
Really good writers strive to write more complicated simple sentences and complex sentences than compound sentences because the former sentences sound more sophisticated and can show various kinds of unequal relationships. If students count the number of simple, compound and complex sentences they use in a given piece of writing, and if the number of compound sentences equals or exceeds either of the other kinds of sentences, that student should rewrite some of his compound sentences.
Even so, compound sentences are used by every good writer some of the time.