Before you teach your third-graders about conjunctions, it's important to assess their grasp on other parts of speech. It is essential that your students understand clauses, because conjunctions are used to link clauses in sentences. A clause is a group of words that may or may not express a complete thought. Those that express a complete thought are called independent clauses and can stand alone as sentences. Those that don't express complete thoughts are called dependent clauses and can't stand alone as sentences; these are connected to other clauses with the use of conjunctions. Have your students practice identifying subjects, verbs and clauses before examining the conjunctions used to connect clauses.
Coordinating conjunctions always join like grammatical elements, such as two verbs. You can tell your students that coordinating conjunctions are like a see-saw, and the sides must be balanced for them to function properly. There are seven coordinating conjunctions -- "for," "and," "nor," "but," "or," "yet" and "so" -- and you can help your students remember them with the acronym F.A.N.B.O.Y.S. Have your students practice working with coordinating conjunctions by creating fill-in-the-blank sentences and having students pick the most fitting conjunction for each.
Correlative conjunctions can be a little tricky for third-graders because two conjunctions are required. You can explain to your students that this type of conjunction uses teamwork to succeed, because the pairs of conjunctions also need pairs of verbs, nouns or adjectives to function properly. For example, the coordinating conjunction pairs of "either" and "or" and "both and "and" only make sense if used in conjunction with like parts of speech. You can't compare and contrast nouns with adjectives. Once you explain the concept of these conjunctions to your students, they may be able to successfully guess other pairs. Other pairs of correlative conjunctions students may already be familiar with include "neither" and "nor, "whether" and "or," and "as" and "as."
Subordinating conjunctions join two clauses, a dependent and an independent clause, so it's helpful to teach and review these clauses before teaching subordinating conjunctions. Explain to your students that a subordinating conjunction, such as "although," "because," "how," "while" and "before," act as an introduction to the dependent clause to help put it on equal footing with the independent clause. Also note that independent clauses can come before or after dependent clauses.