Inform students that the English language contains four basic sentence constructions: simple, compound, complex and compound complex. That means, all sentences students read and all sentences they write fall into one of these four categories.
Diagram the most basic sentence construction, the simple sentence, on a blackboard or white board. A simple sentence contains one subject and predicate, also known as an independent clause. For example: "She walked," or "It rained yesterday." "She" and "It" are the subjects of the sentence because they perform the action of the verbs "walked" and "rained." Write the formula "subject + predicate" on the board.
Copy the formula for a compound sentence on the board: "subject + predicate + coordinating conjunction + subject + predicate." Compound sentences contain two simple sentences joined by a coordinating conjunction, or two independent clauses. For example: "She went for a walk, but it rained."
Write the pattern for a complex sentence on the board: "subject + predicate + subordinating conjunction + subject + predicate." In "She went for a walk, although it rained," the complex sentence contains one independent clause and one dependent clause joined by a subordinating conjunction. Explain that subordinating conjunctions introduce clauses that cannot stand by themselves, or dependent clauses. For example, "although it rained" is an incomplete sentence.
Introduce the most complicated sentence English allows, the complex-compound sentence: "subject + predicate + coordinating conjunction + subject + predicate + subordinating conjunction + subject + predicate." A complex-compound sentence contains one compound construction and a dependant clause, as in, "She went for a walk and didn't take her umbrella, although it was raining."
Instruct students to practice writing sentences for each formula. Have students label the subjects, predicates and conjunctions in each sentence.
Ask students how many different ways they can rearrange the different sentences. Possible rearrangements for a compound-complex sentence include: "Although it rained, she went for a walk and didn't take her umbrella;" "She went for a walk, although it rained, and didn't take her umbrella;" and "She didn't take her umbrella and went for a walk, although it rained."
Explain that skilled writers include a variety of sentence constructions in their writing. Using too many simple sentences sounds dull and repetitive; too many compound-complex sentences can get confusing for readers, as they provide too much information to process at once. Have students practice writing paragraphs with varied sentence construction.