A compound sentence structure shows that two thoughts are connected and of equal importance:
Jenny hid the hen, and Benny tried (unsuccessfully) to hide the cow.
Max maintained that the database needed restructuring, but Laura disagreed.
Remember these four important characteristics of compound sentences:
1. A compound sentence is like a set of twins; each is a separate person, yet each is connected to the other with the same biological "make-up." That is, each has a subject, a verb, and words to complete the thought. Although they are joined by a linking word, each sentence of the compound is complete in itself and can stand alone.
2. The two parts of the compound sentence need to be linked correctly, with a comma and then a linking word at the place where one sentence ends and the other begins. (Otherwise you will have a sentence error called a run-on sentence. Run-on sentences are typically compound sentences without the proper punctuation and/or linking word.)
3. Because there are two complete sentences in a compound sentence, each has equal weight in terms of the ideas being presented. That is, you may want to link sentences into a compound to show that their ideas are equally important.
4. The linking word shows the relationship between the ideas:
and = the 2nd sentence contains the same type of idea
but = the 2nd sentence contains an equal but opposite idea
or = the 2nd sentence contains an equal choice
so = the 2nd sentence contains an equally important outcome or result